 Hi, everyone. How are you all? I hope everyone is doing good. And I can see, okay. Okay. So that's nice to see all of you. I hope my voice is also pretty clear. If there is any lag or drag, you can always let me know. Okay. And I'm sure everybody knows the ground rules, you know, to keep yourself muted. Whenever you feel you can always ask me for any doubt in the chat window. Okay. And keep a pen and paper with you so that you are able to, you know, take down your own notes. Okay. So all of this is very, very important. Okay. Let me see. So that's so nice. I can see Aditi, Ananya, Ritra, Madhumita, Chris, Gurman, Hita. Hita, you're joined from two, you know, just check if which one of yours is working. Shitej, Neha, Netushri, Pradhan, Vishar, Riddhi, Sharvi, Shanmok, Shreya, Tanishka, Viva, Varsha, Veda, Vidul. Very nice. Good. Okay. So, very nice. I welcome you to this session. Let's have, let's, let's, let's study well together and have some fun. I'm sure. Okay. Now, just, just for, yeah, just for the context, you know, please, make sure that, you know, you just write in, you know, all your chats do get recorded and we have people from across, you know, schools and even, you know, places across the country. So make sure, yes, Aditi, I've just stopped the screening. So make sure that you make the most of it. Okay. There could be instances when the speed varies depending on your understanding, you know, so some topics could be slow for you, but if you have patience, then some topics could be a bit fast. You know, you can always put in a note or a comment in the chat box and I will make sure that I reiterate that. Okay. This is a two hour long session and you guys are at your home, you know, you might tend to get a bit cozy with things. Okay. I recommend that you keep your NCRT textbook with you. If you have any other notes also, you know, our class notes, if you are at Centrum, you know, elsewhere, you know, please keep your class notes also with you. And I hope everybody knows that we are going to do assets and basis today. Okay. So we'll look at all the possible topics that will be covered. I can assure you that the things that we speak today in this next two hours will be an exhaustive list of things that will be coming in the NCRTs or which we can expect, you know, very strongly. So, you know, that's how we make all of these PPTs always. Okay. So, yeah. So be with us and keep yourself muted. Most welcome to ask any questions or doubts if you have. Let's begin now. Okay. So the topic that we're going to have today is basically assets and basis, right? Everyone knows assets, basis and salts, you know. Now these are very common household things that we have been using, you know, in, you know, across our, you know, not only foods, but also in, you know, things that are used in houses everywhere, right? Now, those who were not there last time, okay, I'm going to also show you, give me a second, I'm going to open up a presenter. Yeah. Right. One second. All right. So, yeah, there we are. Yes. Perfect. Now, yeah, so for everyone who has just, you know, I mean, who were there in the last class and who were also not there for all of you, this is like a typical distribution of marks from each chapter. Okay. So let's talk about assets and basis, okay, which is basically denoted here with, let me change the color for a bit. Yeah, we have it here. Right. So assets and basis, which is maroon in color. Okay. You can see that this is, you know, seven marks have been asked out of this chapter in 2019 and about three marks in 2018. Okay. Now, last time also I told you that these variations keep on happening and you cannot really predict what chapter would come or not come in a particular year. Okay. For example, you see sources of energy. This is one chapter where there was zero questions that were asked in 2019. But one question came in 2018, right? So a relatively significant chapter, okay, to, you know, really get things moved, you know, with this, I mean, if you have done with this chapter, you know, you can expect at least one or two questions definitely to come in. Okay. Right. So now, yeah, I think people are still joining in and therefore we have all of these, okay. Yes. Now, let's get to the next. What is the next guys mute yourselves? Yeah. So, you know, we have also seen in the last class what is the going to be the exam pattern this time. Okay. So from all the previous years, you would be the first batch that would go through a different exam pattern. You should expect about 14 marks that you would have from, you know, MCQ or 40 to 20 questions out of MCQ and very short answer. Very short answer means you either answer in one word or maybe just a few words, not even a sentence. And then there would be directly three mark questions and five mark questions. Okay. So basically, you know, the total paper being of 30 odd questions, you can expect about five three markers and three five markers and roughly about those many questions. So that's where you'd land up. With options, of course. I mean, I'm talking about with options. So that's your new pattern that we have. Now, let's, let's get deeper into the topic. You know, so we are going to begin understanding the topic. So what is the basic differences between assets and basis? How do we define assets and basis? Now, please note, this is one concept which has more than one definition. It basically has three definitions itself. Okay. Now, this is very strange, right? I mean, have you ever seen that having three definitions that needs to be worked out for a single concept? Now, when it means that there are three definitions, guys, you know, can you, yes, just mute yourself because if you're joining in late, you know, the things that you're working with, you know, really, yeah. Okay. Yeah, just mute yourselves, guys. You know, that really helps. Okay. Yes, fair enough. So this has three definitions, you know, three odd definitions. So the definition that you guys study is called as, you know, its technical name is Arrhenius. Okay. Arrhenius definition. Okay. This is the only one that you study in your textbook. And the definition of assets in this textbook by Arrhenius is one that produces hydrogen ions, whereas bases are those who produce OH minus ions. Okay. So this is the definition. So the, this line that is given here is the definition of what assets and bases are. Okay. And please note, it is only in aqueous solutions. Okay. So it is very important to have that in aqueous solution. If you're not in aqueous solution, Arrhenius was incapable of defining assets and bases. Okay. Now, in our general context, as I said, with NCRT, we only cater to things in aqueous solution and not beyond that. And there are some more, you know, properties of assets and bases that we actually look at. Okay. So one of the important ones that we will be looking at is assets are in taste, bases are bitter in taste. You know, we know the simple test for assets would be tasting lemon. Okay. Or testing, for example, acetic acid. Okay. So both of this really works. The, and bases, you know, bitter in taste, you know, one of a good example of tasting bases. Guys, you know, if you're, if your mic is not working, I might have to simply remove you out of this conversation, you know, because it is just troubling everyone else. Okay. So just make sure that you mute yourself and make sure that your mics are remaining so. Okay. I'll have to set up notifications and make sure that you're muted forever then. You know, so just, just make sure that, you know, at your end, you, you maintain the hygiene. Okay. Let me just figure out who's is that. So I should be able to do something about it. Okay. Just trying, trying, you know, if you're muting and unmuting, which could also be a loose connection at times. Okay. Which happens with a couple of laptops, but, you know, make sure that you are able to manage yourself rather than me having to really do something about it. Okay. Now, right. Now, these properties, so generally, what are the questions that are asked in these is where you need to write the properties of assets and bases. Okay. So having being sad in taste, being bitter in taste, or sometimes even they ask you about differences. Okay. So changes blue litmus to red, red litmus to blue that also works. You know, the corrode metals, few of them. Now, not all bases corrode metal. Okay. Only a few of them do. Okay. Now, especially the ones that are very strong bases or that are bases that are formed from metals. Okay. Like ZIN, ZIN, ZIN OH twice. That's a base that is formed from metal. So these all are the ones that actually are, you know, quite incorrigible. Any OH is another one that gets quite in corrosion. And of course, you know, both of them act as electrolytes. It's not only assets, but even bases act as electrolytes. What do we mean by electrolytes? Something that dissociates. Okay. Something that dissociates into individual quantities like A minus and B plus, you know. So AB just dissociates into A minus and B plus. Yeah. Can someone just point out whose mic is that? You know, would really help out. Yeah. You know, so that I can really work on it. Can someone please help me with that? Yeah. So if you are observing any of these, you know, just try and put it out here so that I will be able to work out on it. Okay. Yeah. So, right. Now, let's talk about what are the examples, you know, the very common examples are HCL, H2SO4, HNO3, H3COOH. And a very common example of bases is NaOH, COOH2SO4. Okay. Yeah. So, both of these. Okay. Right. Now, so we know all of these examples, right? Now, please note, most of these bases are either formed through a metal and you would also see that these bases are the ones that, you know, are very strong, pretty strong enough. Okay. NH4OH is the one that is slightly weak. Okay. So that really, you know, is one that is slightly different. Guys, you know, I, you know, this is... Yeah. Aruv, can you just mute yourself? Is that Aruv or the one that is really, you know, muting and unmuting? Can you please point this out because it's disturbing everyone now? Okay. Let me quickly check. I think it is, yeah, it's muted for everyone, but what's happening is someone has a loose connection. What does that do? No, it generally happens when people mute and unmute themselves, you know, so that's when it happens. So, and it may not be someone's fault. It's just because of a technical glitch, you know. So if you have a loose connection, the muting and muting actually keeps on happening. And I'm sure it is, yes, people also join in, but I don't think that people are joining and leaving. It's just a technical glitch that's there. But, you know, can you, can you please take up this and just check on, you know... Yeah. Yeah, let's... Yeah. Good. Yeah. Just keep an eye and just let me know so that, you know, I can just make him also comfortable because he must also be getting, you know, irritated with the same. Okay. Yeah. Now, let's resume on the slideshow. Yeah. There we are. Okay. Here are some very interesting assets that you can find around in the house. Okay. So, of course, you know, what you eat and everything that goes in. HCL is the core component of your stomach acid. Whereas all the car batteries and cell-curic acids that we have, you know, is there in the batteries per se. Okay. Your car batteries are... You know, even in fact, any large batteries which are used for inverters, you know, they also would convert, you know, would have sulfuric acid in them. Nitric acid on the other side is used in explosives. Okay. So, trinitrotolvine, you know, TNT is a huge explosive which is basically made with nitric acid, you know, and you would find that acetic acid, which is vinegar, you know, commonly known, is used in most of the foods. Anything that you use, you know, where you use soya sauce, for example, or there used to be a food product. How many of you guys remember it these days? It used to be called as Aginomoto, you know. So, whenever you use these kind of food products, and it was particularly used in enhancing the tastes of, you know, some cuisines, so that is all comes from acetic acid. And then you also have, you know, carbonic acid, which is soda's, you know, so all your aerated drinks are basically carbonic acids. Okay. And then you have phosphoric acids, which are flavors, you know. The only flavor that you generally see, you know, whether it is your, you know, all of these cold drinks that you drink, you know, and when we add flavors to them, most of the flavors are some combination of phosphoric acid and the substance. So, phosphates, they are generally the phosphates of what we use. So, pretty common, you know, these are the ones that you find around in the house. Okay. Some of the most important that you definitely should know, and a direct question can be asked on these are the ones that are listed here. Okay. So, what are those? So, one is citric acid. Okay. So, citric acid is basically used in oranges and lemons. Okay. I mean, they contain that, you know, rather than saying used, we can say they basically are contained in orange lemons for sure. And then you have tartaric acid, which is in tamarind. So, all of these acids have to be memorized. Okay. They have been asked in past papers and pretty sure that they can be very well asked. In curd, lactic acid. Okay. In milk also, we do. Especially when milk turns to curd, we end up getting lactic acid. Okay. So, that's the one. And in ant sting or nettle sting, we know we have methanolic acid, which is called as formic acid. The formula for this is HCOOH. Okay. HCOH, which is methanolic acid or formic acid. Okay. So, that's the one that you can actually work with. So, remember all of these combinations. Pretty useful and pretty important to work with. Now, yeah, let's go further. Right. Now, here are some common bases. Like we saw common acids, now we are trying to see some common bases. So, you will find that any OH, most of the soaps would have that. Okay. Every soap that you've seen in the house is either especially the ones that we use with soft water. So, all bathing soaps, especially bathing soaps, anything that is used for cleaning hair, even the cosmetics that we have. It has some form of dilute NaOH in it. Drain cleaners. There are very strong drain cleaners that actually are used. So, that's also something that you can figure out. Okay. And then you have antacids, something that you have for avoiding acid refluxes. So, when you avoid acid refluxes, you will realize that antacids is something that you have, MGOH twice. So, you know, particularly, you know, there have been people who have been asking, just Jellosil have antacid. Not very strongly. Of course, Jellosil is an antacid, but not in a very high quantity, but you know, milk of magnesium, for example, is a, is something that is purely made up of MGOH twice. Okay. And then you have aluminium hydroxide, again used in antacids a bit, but commonly used in deodorants as well. Okay. Common component of deodorants. And ammonium hydroxide, you know, generally used in any ammonium product including things from urea to some medicines, you know, whenever ammonia is being used. In fact, it's commonly, if you go to a shop and if you want to buy this, it's called as ammonia water. Okay. So, ammonia water is what is ammonium hydroxide. And there are different concentrations of these ammonium hydroxide that you will find being used, you know, across places. Okay. So, that's, so these are some common bases in household usage, okay, that we have. Now, the first important thing that we actually know about bases, you know, we should know about as acids and bases is its classification. Okay. There are few classifications that have been explicitly mentioned in MCRT. A few have been just fleetingly mentioned. Okay. So, for example, based on their origin. So, we call them as organic acids and we call them as mineral acids. Okay. The very name itself says something about it, isn't it? So, organic acids are ones which are derived from living. So, this is a model, you know, these are the keywords. So, whatever I'm circling, you know, are the keywords. So, please make sure that these words should come in your answers whenever you write an answer. We'll go through a few answers today also. So, anyone that is derived from living organisms, which are plants or animals, they are called as, you know, organic acids. For example, citric acid, you know, derived from fruits, acetic acid, which is derived from vinegar. Okay. Oxalic acid from tomato, tartare. We have just seen this a few minutes ago. Lactic acid from milk and curd. All of these are derived from, what do you say, you know, living organisms. Some form of plant and animal. Okay. So, that's something that really helps. Okay. Now, what are mineral acids? Mineral acids are the ones that actually are derived from inorganic substances. Now, what could these inorganic substances could be? So, some of them could be basically you know, just like sulphur, you know. So, we have sulphur streams if you go to Yellowstone National Park. I don't know how many of you have heard of this. In US, there is this park. Okay. So, you'll find that, you know, there are sulphur aquifers, which means there are these hotgizzers that come out, which actually deposit a lot of sulphur around it. Okay. Now, there are a lot of acid is formed. H2SO4 acid is formed. It is so strong that, you know, it obliterates completely any life a few meters away from these sources. So, just nothing can survive there. In fact, if you go to the depths of ocean, you know, you'll find that there are living organisms which only can live on sulphur, you know, which are anaerobic respiration. You know, they eat sulphur, they give out SO2, like we breathe in O2 and we exhale SO2. They eat up and breathe in sulphur and sulphur compounds and also, you know, give the same thing out, you know. And then there is HCl, for example, completely derived from chlorine gas. Okay. What is the most important source of chlorine? Most of it actually comes from NaCl. You know, our seas are filled with NaCl. So, a large composition of you know, NaCl will end up making into Cl2. Okay. So, that's from the basis of origin. Okay. So, that's one. Now, let's talk about classification based on strength. So, this was based on origin based on strength. There are strong basis and weak basis. You know, everybody has known this. Anyone who has studied or even slightly would understand that there are strong basis and weak basis. Okay. So, what are the strong basis? Strong basis are those which completely dissociate. Okay. They completely dissociate into ions. Which means that you put, let's say, you know, I'm going to take some easy numbers. Let's say you put 100 molecules of KOH. You will realize that I would end up getting 100 molecules of K plus and I would end up getting 100 molecules of OH minus. You know, K plus and OH minus both. So, that's how strong basis or even for that matter strong acids dissociate. Now, out of 100, let's say only 5 dissociated. That's called as weak acid or weak base. So, in these bases, do not completely dissociate. Now, what is the difference? You know, generally nature has made it so interesting that the strong ones would almost dissociate anywhere from 90% to 99%. And the weak ones, you know, there are a few that would dissociate about 50% to, let's say, 30% or a percent. But most of them would dissociate less than 10%. Very interestingly. Okay. So, they have kept a large variation in terms of what a strong and weak. And therefore, even if you have a qualitative definition, you can understand this definition is not quantitative. It's a qualitative definition, which means we are not exactly seeing how much. You know, we are saying completely and not completely. So, does 99 dissociation means it is not completely no. It means it is complete dissociation, almost dissociated. Okay. So, nature has made this interesting thing that either they will dissociate up to 99% or they will dissociate only up to 10% or less than that. You know. So, that makes this division very, very clear. Okay. It makes very clear distinction between how strong bases and weak bases react. Okay. Now, here are a few more ways in which you can actually classify acids and bases. One is based on concentration. You know, you have dilute acids and you have concentrated acids. Everybody knows what is dilute. Dilute means little acid, little acid and more water. Okay. More water. Okay. What does concentrated mean? High amount of acid. You know, huge amount of acid and less water. You wouldn't say less water, but you would say as compared to water, the amount of acid is high and therefore it is concentrated. And you know, and just as a fleetingly, you're going to give you another, you know, definition of these acids and bases or another you can say a classification of this which is saturated. Okay. So, you have saturated, which means that no single extra amount of acid can be put in. Okay. Saturated means now it is filled to the brim, which means if you add some more like NSE, you know, you are adding salt. If you add any more salt to it, the salt will not dissolve. That is saturated. Similarly, acids also get saturated including strong acids. You know, so a lot of people have a misconception. Sir, strong acids never get saturated wrong. If you put HCl crystals in water, after a certain amount of time, even the HCl crystals will not dissolve. Okay. It will get saturated. So, that is that is the way that is the point where saturated, you know, concentration is reached. And then you have on the basis of number of hydrogen ions or for that matter, hydroxy ions given here. Okay. Please note, guys, concentrations like we have decided acids and bases. Similarly on the concentration, we also have dilute bases and concentrated bases. And then we have on the basis of hydrogen ion, hydrogen ion and hydroxide ion. So, when you have a monoprotic acid, you know, the very word monoprotic means what mono means one or single. Protic means hydrogen H plus. Similarly, you have mono acidic. Now, please note, this is monoprotic and this is mono acidic. Now, point of convention. I want everybody's years to be here. Okay. Very important point. And the point is bases have acidity. You know, very, very important. Bases do not have basesity. Please note. Bases have acidity. What does that mean? How many acids can the base neutralize? How many acids can the base neutralize? So, what does it mean? Let's say I take NaOH-KOH. NaOH can fight with only one HCl. NaOH can fight with one HCl. So, therefore NaOH and KOH are mono acidic base. Mono acidic base. It is not mono basic. So, bases have acidity. Similarly, when you say a di acidic base, like CaOH twice, it means it can fight with twice of HCl. It can fight with twice of HCl. So, therefore CaOH twice is a di acidic base. And therefore, similarly you can have, you know, tri-acid acetic and polyacidic also. This is not polyprotic. This is polyacidic. So, you can have polyacidic base. Very unknown kind of a base. But just for your information, even if you don't remember, no problem. So, there is something called as FeOH5 2- FeOH5 2- So, you can end up getting 5OH- on this. So, this is a pentacidic base. Very, very highly basic. So, these things exist. But on the other side, you know, there is no harm in saying that it is mono-basic or di-basic or tri-basic. So, mono-protic can also be written as mono-basic. So, acids have basicity. What does it mean? How many bases can an acid react with? How many bases can an acid react with? Okay, bases can an acidity. Yeah. So, these are I have a doubt. Yeah, please tell me. Sir, could you give an example for poly-acidic again? Poly-acidic base? Yes. Okay. So, as I said, beyond your context, but a poly, there are multiple of those, you know. So, for example, FeOH3 is the common compound. This actually reacts with additional OH- to make anything from chemical. Yeah. Tell me. Chemical name for FeOH5 Oh, this is a complex, you know. This is a complex. So, it is fair, this is ferric, right? So, ferric, hexahydroxide. Okay. So, this is a complex. Beyond us. Okay. But just remember that, yeah, there are possibilities. There are possibilities that can Okay. Okay. Similarly, there are polyprotic, you know, for example, you have NH4, NH4 plus. This is pretty common, right? So, this is tetraprotic or tetra basic. Please note, this is tetra basic acid. You know, can give 4H plus if required. Can give 4H plus if required. You know. Okay. Good. So, some interesting stuff here. Yeah, sure. Now, let's talk about indicators. Now that we have acids and bases understood pretty well, can we understand how to really recognize them? Okay. So, there are these natural things in nature that can help recognize acids and bases. Okay. So, they are called as indicators. You know, very simply. So, an indicator indicates, right? As simple as that. So, they simply indicate. So, what are these indicators? There are many of those. You know, there are many of those. One second. Okay. Yeah. Right. So, litmus. Litmus is the most common indicator. Okay. And it is, it is something that you can What do you mean by natural indicator? You don't have to really process it. Okay. You don't have to process it to do anything. You just take the litmus paper, you dip it and it will show its color. Okay. So, you know, it's generally found also in leachens, you know. So, it's actually an extract that we take from leachens, which are very sensitive to acids and bases. We will see their colors in just a few minutes. Another few indicators that you have. So, this is the definition. Okay. An indicator indicates the presence of acids and base through colors or through a visible observation. Okay. Through a through an observation is a is a good sentence. You know, you can just add to it through an observation. The observation means something that is very concrete that can help you. So, red cabbage. Red cabbage is another indicator. You know, colored petals of pitunia or turmeric. Okay. Turmeric is another indicator. We also have old factory indicators, which means something that can be sensed through smell, you know. So, they show order. Okay. They show order in terms of basic or basic media. You know. You generally have onion or clove. Very strong order, right? Very strongly strong presence of acids. In fact, I don't know how many of you have also smelled garlic oil. For example, you know, if there is a garlic oil, it is so strong that if you just take a small, you know, I mean, I wouldn't even say a drop, you know. The way that they put deos on your, you know, on the back of your hand, if you just put a small garlic oil there and if you smell it, you'll find that it is a, you know, like a small prick right inside the head, you know. It is that strong. So, try that sometime, you know. So, a very strong old factory indicator can be found in garlic oil, for example. Okay. Now, this is very, very important. Okay. All of this, you need to memorize and remember. Okay. Very important slide. Please note blue litmus. This is very easy. Everyone knows that in acids they change to red. In acids, everything remains red. Please note red, red, you know, either it will have no change or it will remain red. So, remember, acids is like danger, you know. This is how you can remember it. Acids is like danger and therefore it is red in color. And if you want something in bases, so in bases, you will find that you actually end up going everything to blue. Okay. Blue is the color that bases you will find in bases. Okay. So, blue here and red here. Now, methyl orange, the slight difference, instead of going to blue, it actually stops at yellow. Okay. So, methyl orange in bases stop at yellow. In acid, it is still red. Okay. And phenolphthalein, instead of again going to red, it stops at pink. So, these are the two outliers. So, remember, phenolphthalein, which is colorless by choice in, I mean, by nature in acids become pink. Okay. Another very important point, people don't have this idea about it. Except for litmus paper. Although they also help, all others can be repeatedly used, which means if the solution becomes base, you will find yellow. But then if you make the solution again, it will go to red. They can be used multiple times. They cannot be they are not single use products. But for example, litmus paper, you know, before going to multiple use as you know, it will lose its ability to show color change. Okay. Now, and this is the universal indicator. Now, please note, universal indicators in the acids are also red. In basis, it generally goes to blue. Okay. And if you have to remember this, you know, you have to remember Vibgior. So, Vibgior is what we, I, B, the rainbow colors, right? G, Y, O, R. You can see, the universal indicator also follows the same color pattern. You know, as you are strongly acidic, it is red. It starts becoming oranges, you know, at lesser acidities around pH value two. So, please note, these pH values is not something that you need to remember. No point in remembering these pH values. No, not needed. But what you need to remember is in acidic, what it is, generally, as you start going towards neutral, you will find that it is green or dark green. Okay. So, if you are more towards acid, say green. If you are more towards the neutral side, you say dark green. Okay. And when you start going away from the neutral, okay, which is seven, you know, it starts going to be blue. And in fact, you know, your textbook actually says that even at 11, 12, it is dark blue. Dark blue. Siddhisth, can you please identify this, the one that is really, you know, Siddhisth, Veda, can you just please make, you know, okay, Veda, Arithra, you know, I would be really happy if you put this sort of productive use, you know. Why don't you guys just make sure, you know, Veda and Siddhisth, can you just please, you know, help me identify that so that we'll also be able to help the poor chap, because he'll be hearing half the session and also be putting others to loss. Medha, Medha and Nithushri, can you just make sure that you mute yourself, Medha. Yeah, Medha, I know that you have this last time also, there was an issue with your mic. Okay. Yeah, that's Medha. So, let me just make sure that I, okay. Thank you. Thank you for that. Nithushri, just, you know, if you have a loose connection to your end, you know, just make sure that you maintain that. Yeah, that's actually Medha, I can see that now. Medha, you know, can you just, if you're there on the phone or something, you know, can you just make sure that yeah, much better. Thank you. Okay, great. Let's get back, okay. Right, so that's a universal indicator for us, okay. Now, we are coming to the chemical properties, okay. Now, generally, most of the time, this question is asked to give you a certain particular reaction, okay. So, generally, they would ask you to say what happens when metals are put in acids or what happens when metals react with acids, okay. So, you'll realize that when metals react with acid, hydrogen is given out everywhere, okay. This is a important observation and a salt is formed, okay, and a salt is formed. Now, there are many examples that I've given you here. I've given an example of HCl. I'm also given you an example of a very weak acid, which is Cs3COH, okay. Please note, even with Cs3COH, which is a very bulky molecule, zinc does form a zinc salt, which is ZnCs3COO twice. Please note that twice. Zn has not lost its valency of 2-year also, plus 2, plus 2, plus 2-year, you know, ZnNO3 twice. And you find that everywhere, hydrogen is given out, okay. A common question that would be asked is, a metal was put in a solution and it gave a pop test, okay. What is a pop test? So, you generally put a burning candor or generally the word splinter is also used, okay. Splinter or a candle or a mat steak, you know, anything that is going to give you some fire, okay. And when this is brought close to the test to you, you know, you will find that a pop sound or an explosive sound, okay. It's basically a small explosive sound is given out. This test confirms that there is hydrogen, okay. So, please note what are the wordings, you know, when anytime you have these wordings, definitely know that H2 was given out. And if there is a metal that is involved, which is giving H2, it has to be acid and also base. And I am going to come to base in a few moments and I will also tell you how to distinguish between acid, whether it is then acid or a base or not, okay. But this is the reaction of acids with metal, okay. So, what is the reaction? They end up giving you know, salt and hydrogen gas, okay. Now, let's talk about next. What does bases do with metal? Now, only, you know, NaOH and Al, okay. Only zinc and aluminum are the two that are mentioned in your textbook. I do not expect any more coming. In the past 10 years, it has not come. Even now, it will not come, okay. So, please make sure that you write this pretty well, okay. Now here, the formula is NaAlO2, please note. This is Na2ZnO2 and this is NaAlO2 also called as aluminate, okay. Sodium aluminate, okay. That is zincate and this is sodium aluminate. Both of these formula are very important. You write this as 3, you lose your marks. You write this as 2, you lose your marks. You write this as 1, again you lose your marks. So, very important. And this also ends up giving PopTest. This also ends up giving PopTest. So, NaOH plus zinc ends up giving sodium zincate and sodium aluminate and you have your hydrogen gas released giving you a PopTest, okay. Now, such reactions are not possible with all the metals. As I said, remember only zinc and aluminum as the example. That too only with NaOH, okay. So, this is the one that is there in your syllabus and will help you. Okay. Now, let's go to action of acids and bases with metal carbonates and bicarbonates, okay. What happens when an acid reacts with metal carbonate or bicarbonate? Obviously, whenever a carbonate or bicarbonate is given out, this is the more important vital you know, component. What happens is Na2CO3 plus HCl will end up giving you NaCl water and CO2. Okay, NaCl water and CO2. Now, how do we know? So, we cannot detect NaCl directly. We cannot detect water directly because water is there in the solution all the time. But CO2 can be detected through a test which will come in a minute. So, this reaction is when acids plus anything that contains CO2 will have to release the CO2 which can be very easily detected, okay. Similarly, metal bicarbonate plus acid can also end up giving sodium, you know, carbon dioxide salt and water, okay. So, NaCl3 and CO2. Okay, this can also be given out, okay. Now, what is what is the test for? So, pop test is for, you know, hydrogen. What is the test for lime water for CO2? The CO2 test is lime water. What does it mean? Please note, there are two tests here. Half of the people only write one test and I said this in the last time. I said this in the paper explanation also last time. So, the first test is whenever CO2 is passed through lime water which is aqueous CaOH twice, aqueous CaOH twice, lime water, okay. You will realize that CaCO3, a PPT is formed which is white in color. So, this color is important, PPT is important. Now, if we pass excess CO2, this is the second test. So, this entire thing is first test and this is the second test. Please note if CO2 is passed for very long milkiness disappears and calcium hydrogen carbonate which is soluble. For example, CaCO3 plus H2O plus CO2. If you keep on passing more CO2 in it for a long time, you will find that sodium bicarbonate or calcium bicarbonate or calcium hydrogen carbonate is formed which is soluble. So, your PPT dissolves. Both of this should be written. If they have given you one test, that is okay because you are going to identify the substance, you identify as CO2. But then you are going to mention that how will you detect CO2. It is mandatory to write both the test. I will say this one more time. Even if it is a two marker, I have seen this in papers in two markers, they expect four keywords. So, what they will do? They will say white PPT is the first the entire thing is first keyword insoluble as the second keyword soluble on excess. That is the third and fourth keyword. In a simple way, they will give you these four and if you do not write all of those four, you end up losing marks. That is the important aspect of chemical properties of acids and bases. Lime water test of CO2. Now, the third reaction which is common for both acids and bases is the neutralization reaction which is base plus acid end up giving you salt and water. So, NOH plus HCl gives salt plus water. The neutralization reaction when the effect of base or for that matter of acid is nullified by the base or vice versa to give salt and water. So, this is the very... I am not going to spend much time on this. Everybody knows this reaction pretty well. What I could do is I could... One important thing that could be challenging here is sometimes, not challenging I would say but that you have to definitely remember which I have spoken about in chemical reactions and equations is write the state and balance. If you do not write the state and balance then you end up losing marks. A typical example given is what happens when something like DAOH twice reacts with let's say unlikely but giving you an extreme example CS3COOH. So, you would say CS3COOH twice barium. So, this is barium acetate. If you write it barium at the beginning, no problem. Don't think that it only has to be written at the end you can write at the beginning it doesn't go wrong. This is barium acetate plus water and then you have to balance it. There will be two in here and there will be two in here. So, the balancing is required. This is aqueous. This is also aqueous and this is liquid. So, the balancing in state is something that is important else you tend to lose your marks. Now, chemical properties of acids and bases this is sorry, yeah. This is reactions of metal oxides. Now, for everyone who either have studied with me or not otherwise please note all metals I should introduce the word almost. Almost all metals all metal oxides and all metal hydroxides are basic in nature. Please remember all metals metal oxide, metal hydroxide. Let me give you an example potassium. Potassium is basic. Potassium oxide is basic. Potassium hydroxide is basic. Let's talk about sodium. Sodium is basic. Sodium hydroxide is basic. Sodium oxide is basic. Sodium hydroxide is also basic. And exactly the reverse for non metals exactly the reverse for non metals. So, all non metals oxides and non metal hydroxides are acidic in nature. Let me give you an example. Let's take N nitrogen itself. Nitrogen is acidic. N2 is acidic. It's inert in more ways but if it reacts it will react like an acid. NO2 or simply NO or N2O3 any of those they are all acidic. They are the ones which form HNO3. They are the ones which form HNO3. Then HNO H3PO3 HNO3 is also nothing but NO2OH This is nothing but HNO3. It can also be written as NO2OH. This seems to be like an hydroxide with an OH but it is an acid. Everybody knows HNO3 is an acid. Similarly H3PO3 can also be written as POH3 doesn't mean that it is a base. It is still H3PO3 and it is quite an acid. It's quite an acid. Most non-metals non-metal oxide and non-metal hydroxides are acidic in nature. And then there are some which are in the fringe which lie in between these two. They are amphoteric. Two classic examples that I can always give you is ZNO or ZNOH twice. Another very classic example that I can give you is AlOH twice. Both are amphoteric. What do you mean by amphoteric? Sometimes they will show acidic. So basic. Neither here nor there completely. Acid can be basic both. So whenever metal oxides are going to react very remote chance of reacting with base. Not possible. Why? Because they themselves are basic. We just studied. Metals, metal oxide and metal hydroxides are basic. So they will react easily with acids. Only these two are the ones which will react with base and we just saw a few minutes ago that they form sodium zincate and sodium zincate respectively. I have already said this a few minutes ago. Right. Coming back. Take a note of this. I hope everybody is taking down these key important points. Some thumb rules that you will always remember and will help you in any time in the exam. Now, if you know this then what is the important point that you take any metal oxide like CuO, put it in HCl you will end up getting copper chloride plus water. So base, this is basically a base plus an acid ends up giving you salt plus water. Same reaction. Now this appearance of blue green color. These colors are also another important point of the solution. So this will be your blue green which is your CuCl2 is because of the formation of CuCl2. You know, so yeah. So I've already told you this point. Right. So this is another important metal oxide reactions of acids. You can also expect that they will end up giving you metal hydroxides. Which anyways you know most of them would be basic. Here is an example. CaOH2, metal hydroxide reacting with a with an acid. Okay. So this is non-metallic oxide. This is a wrong example. Okay. I'm sorry. I don't know how this popped in here. So this is nothing but this is a metal hydroxide. This is a metal hydroxide reacting with an acid. CuO2 is an acid here. Please note it is a non-metal oxide. Oh, okay. Hey, this is the right example. But what they have done is they have simply flipped it. So non-metal oxide is this actually. You know, CuO2 is a non-metal oxide and this is the base. So they have flipped it in some ways. So it should actually be written as CuO2 plus CaOH2. Okay. So this is your base and this is your non-metal oxide. Okay. So this is non-metal oxide. Now we have just seen a few minutes ago. Non-metal oxides are acidic in nature. This is a base that ends up giving you salt. Okay. Ends up giving you salt which is nothing but CaCO3 plus water. Okay. Which is nothing but H2O. Okay. So non-metal oxides are said to be acidic in nature because of, because on reacting with the base they produce salt and water. Okay. So this is your non-metal oxide plus base. Now. Now we want to talk about strengths of acids and bases. So a few minutes ago we spoke about strengths of acids and bases where we did qualitative definition. Even here we will have this definition as qualitative only. We are not going to go to a very quantitative definition per say in terms of strength. But there is some indication. You can go close to defining how strong or how weak it is. You are just going to estimate how strong or weak is that happening. Okay. Now. So this strengths of acids and bases they basically depend on H plus ions and OH minus ions. That's how they work with. Okay. Now. So there are multiple ways. Of course with universal indicator you get a very good idea as to how strong or how weak that acid is. You know, I just told you remember red for acids, blue for bases green for neutral. Then you can do two more things on it. You can put orange, you can put light green, dark green light blue and dark blue. You know, you can bring in so many variations in it and cover your pH pretty well. Okay. Now. So whenever this universal indicator is used you get a relative idea of how strong or how weak it is. Okay. But there is a more definite indicator which is the pH scale. This pH word comes from Potens, you know, which basically means power in German. Okay. So in German, you know, German language, it means power. Okay. So power of hydrogen. That is what we really work with. Okay. Now this scale is generally from a 0 to 14. Now this is mysterious. No, it is not 10. It is not 5. It is not 8 octet. It's 14, you know, and you know, just to give you an idea about this is because in nature it was found that H plus into OH minus concentration in water is always equal to 10 to the power minus 14. This is found in nature. Okay. And therefore this this 14 comes in. So this is like another constant like five, you know, 3.1425 you know, to whatever, you know, that long five value is similarly 10 to the power minus 14 is a constant found in nature, which was the multiplication of the concentrations of H plus and OH minus generally called as ionic product of water. Again beyond our syllabus, but for your, you know, to have you a small amount of curiosity on this that we exactly have them same, right? You have if you have H plus and OH minus same, what will happen? This will be H plus square, you know, H plus concentration, the whole square to the power 10 to the power minus 14. So H plus will turn out to be 10 to the power minus 7. And therefore, whenever it comes in, you end up getting neutral very easily. You know, so whenever you get your pH value as 7 you will have neutral value. Okay. Guys, I might not be able to read your comments right now, but you know, you're free to you know, open up your mics and ask like someone did recently, you know, so completely. Okay. If you have put any comments at the end of the session, I would definitely go through them. Okay, so yeah. So that's one, right? So you neutral is 7, alkaline is you know, so remember pH is like a rank higher the rank more the acidic pH is like a rank higher the rank, which means if you are ranked one, then you are very, very acidic. Okay, so you're very powerful and very acidic. Now, there is also something called as a pH paper. Okay, it actually also is very close to universal indicator with small synthetic additions to it and you can actually measure pH out of this. Okay, you are able to measure the value of exact value of pH from here. Okay. Now, let's talk about the strengths of acids and bases, you know, so when you have pH values of zero to, you know, where your pH paper value value, you know, so your color of pH paper would be about dark red, you know, we just saw this, your universal indicator color is also dark red, right? The solution is highly acidic, you know, H plus I am concentration will be very high and OH minus will be very low. If you are somewhere around four, you know, generally about orange to yellow color, you are just acidic, you know, from zero to four you are just acidic, you know, moderately acidic, you can say. H plus I am concentration is high and OH minus would definitely be low. Please note, OH minus concentration still are present. Does not mean that OH minus are not present in the solution at all. It simply means that H plus are much, much larger than OH minus, like a million times larger, like a million at times, times larger, okay? So that's the concentration equivalent. When you are at seven, you know, the value is generally about green and you will find that the H plus and OH minus values are just the same, you know, it's just the same, they are equal, you know, and then you can go just the opposite, right? So at ten, you will find that blue is green or blue and at fourteen, you will find dark blue or violet, like with VR, right? We spoke about it, violet to about red with VR. Now, highly basic, very low, very acidic and here are some examples at CL, H2SO4. Now, you know, someone asked me lately that what is H2SO3? H2SO3 is a weak acid, please note, it is not a strong acid. H2SO3 would be categorized under under weak acids. So H2CO3, H2SO3 even, you know, phosphorus acids are all weak ones. Now, what are the strong base is NaOH, KOH, CaOH twice. What are weak ones? NH4OH. Okay, NH4OH is the good example of a weak base. Right. Now, let's go further. Yeah. Now, now, why are we studying this pH? You know, what's the what's the role of, you know, why pH, right? So it is very important in our daily lives also and there is this question that directly comes here. Now, state the importance of pH in your daily lives and then it's generally a three marker. You generally have to give up to five points. There are many points that I've mentioned in here. For one, it is very important for our digestive system, you know, our pH in our digestive system is regulated to digest the food. Similarly, it is also regulated in our blood, you know, for that matter. Okay, that's that's also very important. Our blood is, you know, slightly alkaline, you know, generally about 7.1, you know, 7.1, 7.2 max. Okay, slightly alkaline. So very close to neutral, but alkaline. Yeah, then of course, you know, and then there is acid reflux that you can speak about in for body, bodily points, you know, you can speak about antacids. That's also something that is important in pH. So if we know pH, we are able to figure out all of these values, you know, we are able to treat the pain and irritation in our stomach because we understand pH. Okay, so antacids I've already mentioned it here. So these antacids neutralize the excess acid and we get relief. Then you can also speak about acid rain. Okay, so acid rain generally has a pH less than 5.6, you know, generally called as acid rain. In fact, you know, this question was asked in the IITs. I've mentioned it in few of my classes. This last year, it was asked in the IIT that what is the pH of the acid rain? Can you imagine your syllabus question asked directly in 12th grade and very few were able to actually give it a right value. This value was asked last year. Now, when acid rays flow into the rivers, they get acidic and cause threat to survival of aquatic acid, sorry, aquatic life. And you can also speak about plantation, you know. So the soil, the pH of the soil is very, very important for the sustenance of the plants. You know, the pH of the soil also decides what will be the life of the particular plant species that you are planting. Yeah, so I mentioned it here. So a few more points. You know, I've given you many of those. You can pick up any 4 or 5. So your pH of soil, so there is a specific range in which only few plants can grow healthily. There are few plants who can stretch this range and still survive, but that doesn't mean that they are growing healthily. Now, adding a lot of fertilizer sometimes changes this pH. And that is also very harmful. In fact, addition of pesticides also works on doing that. So, you know, ball bodily function generally would range from 7.0 to 7.8 in living organisms. So even our life, you know, in fact pH of our air around us, pH of the water that we drink, pH of the bathing water that we have, all of that is very important. So therefore, if there is a very chlorine high water, you will find that, you know, your skin becomes very dry, because the pH of chlorine high water is very, very acidic. A very highly acidic chlorine water. So when you go for swimming, for example, and you must have heard this in daily conversations, I am having a hair loss because my water is very acidic. So all of that are problems of not having a good pH. Tooth decay. In fact, you know, you should try this experiment at home and I am sure most of you must have seen this video. If you take your tooth and put it inside a Pepsi or a Coke for a day or two, the entire tooth will dissolve. And do you know that your teeth are the strongest organ, you know, it has the, you know, your jaw muscles has the largest strength, you know, if large is the right word there. In terms of the power that you can exert, you know, your muscles, you know, do not really, you know, your hand and feet muscles or, you know, other leg muscles do not have this. Your jaw muscles are the strongest in your entire body. Your teeth are very, very strong. But, you know, that entire teeth can dissolve, you know, in pHs as close as to carbonic acid, which is about 3.5, you know, 3, around 3. So in Pepsi, if you put your tooth, it will dissolve in a day or two, you know. Using toothpaste, you know, using toothpaste in the right way is also very important. Beasting, you know, it is another, you know, be like insect, you know. So it causes pain and irritation. Again, an example of, you know, knowing pH. So you use a baking soda, because beasting is acidic, you use a baking soda to neutralize it and to get relief. Now, so we have just seen pH values. Now we will talk about salts. Okay, what different types of salts could be present and what have we done about them? So what are salts firstly? So they are ionic compounds generally produced by neutralization between an acid and base. All of these words are important. Okay, ionic compound. They have to be ionic. Second, they are a result of neutralization between whom acid and base, okay. Electrically, they are neutral, you know, electrically. There is this electrical word, which means that if you put electrodes inside of them and if you want to, you know, just simply measure, you know, which way this way, you will find that most of the times they won't, even if it is between a weak acid and a strong base, you know, like acidic or basic salt. Yeah, now there are a number of salts, okay. So sodium chloride is one of the most common salt, you know, we use every day in food, you know, sodium chloride as table salt, common salt. Firstly, they are crystalline. What do you mean by crystalline? They have a definite shape and also a regular pattern of it. You know, they have a regular pattern of it, you know. So just for your understanding, NaCl has a very interesting pattern, okay, it's cubical. So this is our NaCl molecule, not molecule, you know, in fact, it is one giant molecule. I hope everybody understands what is the difference between a molecule, molecular mass in fact, and a formula mass. I have said this last time or some, in some classes, you know, it's formula mass actually. So, you know, there is no molecule of NaCl at such, you'll never find NaCl molecule in nature. How does it exist? It exists like Na, Na, you know, alternately placed, these are all Na and then chlorine, they're placed here, okay, so alternate chlorine. So this is Na, this will be Cl, this is again Na, this will be again Cl, again Na. So it is one giant molecule, but then why do we, why are we not writing Na 1000 and chlorine 1000? Because, you know, these numbers also vary, these numbers also vary. Sometimes you might have that entire structure made up of one mole, 10 to the power 23, such molecules continuously arranged, perfectly, perfectly grown crystal. So in that case, what do we do? We just write the ratio. So we know that for every Na, I'm going to get at least one Cl. To your surprise, ZnO also behaves as a crystal, okay. And there are many of these, there is this tellurium oxide, T O2. So here for every tellurium, twice of oxygen are produced, are present in the crystal. You'll find that the entire crystal lattice is made up of T and O2. Which makes sure that, you know, the ratio between tellurium and oxide is 1 is to 2. And therefore you will find that this is one molecule, you know, this is one V, you know, that you are able to find crystalline solids, right? So that's crystalline solids. Now, most of these salts, they generally are opaque, but they could be transparent also. Okay, so quite possible, you know, transparent salts being present. And very very important, all of them, you know, almost 99% of them are soluble. Why? Because they are ionic in nature. If you're ionic, you will naturally be tending to be soluble. Okay, so that's solubility. Now, solution of salts definitely conducts electricity, you know, in molten state also. Now, please note, salts do not conduct electricity only in solid state. Why? Because there is no, nothing to move charges. But if it is molten, generally also called as fused state, molten or fused state, both are the same words. Or it is in dissolved or aqueous. Okay, dissolved or aqueous state. Again, the same words. Okay, they are the same in meaning. You will find that they conduct electricity. Now, they could be, of course, salt will be. Salt intake, they could be sour, sweet, bitter, you know, savory, multiple different tastes. Neutral salts also are odorless. Some, you know, salts can be colorless, colored, there can be different, you know, so all these variations are possible. Because salts themselves are formed by two basic ingredients which can be mixed in variable proportions and different types can be mixed and brought to them. Okay. Here are a few types of salts. Some types of salts. Neutral salts you have. So you have a strong acid and a strong base, you know, so neutral salt will have 7 pH. And then you have acidic salts where you have strong acid and weak base. Salt made up of strong acid and weak base. For example, here there is NH4Cl. So NH4Cl is made from ammonia and HCl. Okay, ammonia and HCl. Or in other words, NH4OH okay, NHCl will end up giving NH4Cl plus water. But please note NH4OH is weak and HCl is strong. Now, Whomsoever is the strong will be the one that will give the property to its salts. So acidic salts are strong, are salts because they are made from the strong acid. Similarly, basic salts will be made from strong base and if it is both, if both of them are strong, strong then it is basically a neutral salt. And what happens when both of them are weak? In that scenario also please write neutral salts. Okay, there are variations in it beyond our syllabus. Please write that as neutral salt. So weak acid and weak base. If they form a salt, it will be termed as neutral salt. Okay, right. Now, another important question. There was confusion among this and therefore very few have been able to really say about it. So there are family of salts. So there is an entire list of family of salts. Okay. So what do you mean by family of salts? Now salts having common acidic or basic radicals are generally the family of salts. So what do you mean by common acidic and basic radicals? So let's call for example, sodium chloride and calcium chloride. Okay, so that is CaCl2. So it is called generally the chloride family. Isn't it? Now calcium chloride and calcium sulphate will be called as calcium family. So please note single salt can be a member of both the families. So it can be a member of chloride family also and calcium family also. Okay. Is acidic salt and basic salt a family? No. So if you are saying acidic salts and basic salts generally not termed as a family of salts. No, not true. So in a lot of exams I find that when students are asked that please write the family of salt. All salts that are acidic in nature are acidic family of salts. Wrong. Basic no. It has to deal with radicals or in other words ions, in simple words ions. So the ion has to be common. Okay. So in sodium chloride chlorine, anyone who shares chlorine, tomorrow even if I take ZnCl2, it will be a chloride family. Okay. So this is very important. Okay. Not ZnCl2 and ZnS4. It is a zinc family. Okay. Now can salts be a part of more than one or more than two families? Yes. I'll give you an example. Our very own example of Na2ZnO2. This is a family of salt of sodium family of zinc family and also of oxide family. Sodium family, zinc family and oxide family. So you can be a member of three different families. Okay. You know, pretty easy question. No point in losing one odd mark here. Okay. So you should definitely get a mark here. So just look at what these radicals are and you should be able to figure out what family it really belongs to. Okay. Now now we are going to talk about the last six. Okay. So I I'm giving almost you know nearly about 40 odd minutes for this. Okay. Very important and there are just the six compounds that we really are talking about. What are those the first one is NaOH. Okay. Second one is Na2CO3. NaHCO3. Okay. So sodium hydroxide, sodium carbonate, sodium bicarbonate. We will also be talking about you know, bleaching powder CaOCl2. We'll be talking about gypsum that is CaSO4 into you know water right. So you have twice H2O and you have Plaster of Paris you know CaSO4 half H2. Right. Both of these and okay. Are we done 3, 4? Yeah. So we have done with them right. 4 and 2. Yeah. All of these are taken care. Right. Sometimes you also speak a lot as a small portion about NaCl. Okay. Small portion about NaCl. Now in all of these you will find that there are generally three very important points. So this is the list of the six compound that you really need to remember. Okay. Six or seven you can say with NaCl if not with NaCl only others are six. What are the three different points that you need to remember about them? Okay. So there are there are these following points that and I've given this to you for everyone in the class also this formula. Okay. So what is it? Firstly, you need to remember its preparation. Okay. Secondly, you need to remember either some of its chemical properties. Okay. So what they really belong to and what needs what they can do and lastly they should you should remember their users you should at least remember three points in each. Okay. You are to keep you know to make your life safe. You remember to remember three points in each of these. Okay. And I'll try and show you all of these as we go forward. You know, I sometimes have mentioned only one or two but I'll give you the third also as we speak. Okay. Now the first point in let's talk about sodium hydroxide. Now in sodium hydroxide the first point is about preparation. Now the process is called as chloralkyl. A very common question is asked is why is it called as chloralkyl? The chlor word comes from chlorine alkali word comes from alkali that is found which is NaOH. Obviously you are making Na sodium hydroxide that has to form. So chloralkyl process comes from chlorine and NaOH. Now this means what is you know so what is the process it is by doing electrolysis of brine water. You know why don't we call it just a salt water. Brine water is 28% by weight salt dissolved in water. You don't need to remember it just for your understanding. Brine water is a very specific concentration of salt that is dissolved in water. Okay. Whenever you take that water and you electrolyze the ratios of the concentration of Na plus Cl minus H plus OH minus all of that that is there in the water is so good that you will get maximum output of getting NaOH. Now see how does that happen. So you know your electrolysis diagram has to be written. I am drawing it for you here. Very important. Okay. The entire electrolysis diagram has to be written. How so you draw two electrodes. Okay. Please make sure that the connections made are correct. This is going to be anode and this is going to be cathode. So anode is here cathode is here inside the solution you have four ions which are those Na plus H plus Cl minus and OH minus obviously between Na plus and H plus Na is more reactive. So it will stay in solution. You will recall this from chemical reactions chapter that we revised as well as in metals and non-metals we will see. So between Na plus and H plus H plus is going to get eliminated in the fight and Cl minus and OH minus Cl minus is going to get eliminated. So H plus will end up turning to the negative electrode that is the cathode. So the cation H plus ends up going here and the OH minus ends up going to the anode. Okay. Now this is very very important is that the half reactions also are something that you might need to write. You know there is a direct question that can come. Please write the half reactions of anode and cathode. So this is what I am giving. Please take a note just in case if you feel you know that helps you at anode it so happens that twice of OH minus ends up giving twice of H plus. Please note H plus is released back to the solution. Okay. One second. Not OH minus. I am sorry. There will be chlorine coming out. So this is not true. Damn. I lost that. No problem. I will destroy it one more time. Yeah. So at anode I was saying you know at anode it is this chlorine twice of chlorine not twice has to be balanced ends up giving Cl to plus 2 E minus quickly drawing it back. So here you had this. Okay. So this is positive. This is negative. This is anode. This is cathode H plus going here. Cl minus going here. Okay. Na plus and Na plus and OH minus staying in the solution. So at anode chlorine goes to the anode and it ends up giving electrons electrons to the anode which further flows to the battery. Okay. And at cathode the half reaction is that twice of H plus takes into electrons and ends up giving hydrogen gas. Please note gaseous your aqueous aqueous all of this is very important. Okay. This is gaseous released arrows have to be written. Okay. Now. So chlorine gas generally you know a slight green or greenish in color good to mention hydrogen gas pop sound good to mention okay. So this is these are the half cell reactions of sodium hydroxide. Now what are the uses now any OH is the most commonly used base. Okay. In laboratory for any titration for any you know predicting what are the compositions or concentrations of acids in titration you can say okay. So it is most commonly used base in industrial processes basic hydrolysis for using polymerization where you make poly clean bags or you make you know cloths or you make any material you know polymer material. Another important use is to make soaps. Okay. Which is very commonly used to make soaps you basically do basic hydrolysis of esters basic hydrolysis of esters you will be looking in carbide compound chapter also therefore I have not really included it here. Okay. But that's another use so many many uses then I also given you a few uses at the beginning of this chapter you know any OH is also a part of lie or your cosmetics. Okay. That's also something that we have seen at the beginning of the chapter. So that's sodium hydroxide now let's go to the second important component okay which is bleaching powder now a very common question a lot of students have been asking in some textbooks it is written as C A O C L you know don't bother please note this is what has been followed and in the model answers I have checked it is written as C A O C L 2 in model answers. So go for go with it this is my recommendation rest is your choice. What you can do is so this is your bleaching powder now it is done with slick lime okay slick lime okay now I have given this n number of times in my classes also the cycle of lime okay so there is quick line okay there is lime water so I would like I would write slick lime before it okay lime water okay and limestone okay so limestone this is C A C O 3 okay lot of water completely aqueous okay please note C A O H twice aqueous is lime water slick lime is C A O H twice liquid liquid okay high concentration of water but not filled with water this is a solution please note this is a solution this is a pure liquid C O H twice slick lime okay and quick lime is C A O okay so this is the calcium cycle you can remember the calcium cycle water you know you keep on drying here and you add keep on adding water so you add water you get slick lime you add more water you end up getting lime water you remove water again you end up getting limestone you remove more CO2 you end up getting quick lime remember these important terms are used repeatedly in the odd syllabus okay so this is the cycle of calcium okay calcium oxide or hydroxides I hope you guys have taken it down okay now so calcium hydroxide whenever it reacts with chlorine ends up giving bleaching powder that is C A O C L 2 okay and this bleaching powder is used in multiple ways see it's basically core function and now is to give back chlorine okay but not in the form of gas in the form of C L radicals C L radical is without a charge which is just atoms this C L radicals reacts with anyone and everyone that comes in present presence with it okay for example it forms H C L if there is OH minus it forms something called as H O C L hypochloric acid okay anything it oxidizes it's a very very good oxidizing reagent okay very good oxidizing reagent what does that mean that it oxidizes anyone and therefore it gets anyone and anything colorless okay so if you basically what we do now we have seen that bleaching action they also bleach your skin why because you know if there are any pigments which are coloring you know the skin the oxidation takes out those pigments so these are not only skin but you know even cloths you have seen that you know if there is if you want to if you want to bleach something what do we do we want to take out the color which is unnatural to that fabric we do bleaching action so the COH twice with chlorine does this bleaching action so it's used as a disinfectant in it's also used in swimming pools it's used in purification of water now it also kills bacteria okay for that matter it also kills bacteria okay sorry once again right so so bacteria and all of these all you know help so I've given you four different uses of bleaching powder one oxidizing reagent disinfectant I've already given disinfectant in also drinking as well as swimming pool water you know pool water and I've also given you another one where you know it textiles it's used in textiles to decolor decolor things right so factories it's already mentioned here factories laundry yeah fair enough you know that's that's good enough okay so there are these are a few uses so that's one now let's go to the next compound which is baking soda okay another very interesting and important compound okay so what is baking soda yeah now please note there is a difference between baking soda and baking powder baking powder and baking soda are different things not the same let's talk about baking soda to begin with so baking soda is sodium hydrogen carbonate okay now how to make make that okay so there is so this process the official name of this process is solvace process whenever I ask students what is solvace process you say sir we don't have that in our syllabus no this process is called a solvace process okay so what do you do you take NaCl you take water you pass a lot of ammonium through it okay so there is an intermediate product that is formed here which is ammonium initially ammonium carbonate NH4 twice this further forms ammonium bicarbonate NH4HCO3 and when this reacts with NaCl you end up getting NaHCO3 okay plus NH4Cl and this NH4Cl is again reused to form NH4CO3 so the cycle keeps on going but without getting into the details I am just sharing this because that will be additional information that can remain in your head you know these these compounds will reverberate in your mind and you will be able to really remember that much more vividly therefore I am giving you these details okay so what happens is NaCl when you put with water CO2 and ammonia you end up getting NH4Cl and NaHCO3 okay both of them is possible now yeah right now okay right so now once NaHCO3 is produced you know this is the reaction chemical reaction which is also important for you you can just simply heat it up to end up getting you know sodium carbonate which is what is you know washing soda but with water of crystallization which we will see in the next slide but the point that I am trying to make here is with just heating sodium bicarbonate this is bicarbonate you end up getting sodium carbonate with water and some CO2 released of course this CO2 produced now in making baking powder you know it is how do we make baking powder what is the difference anyone is asking a question you have a question okay so how do you make baking powder in baking powder basically what do you do is you put up a small amount of acid in it okay so acid plus NaHCO3 is baking powder I repeat one more time just NaHCO3 is baking soda ends up giving CO2 and makes dough fluffy or makes cakes and pastries rice all of that used in baking but if you use NaHCO3 with small amount of acid then what happens is whatever CO2 that is coming out you know it actually forms you know or whatever sodium that is also coming out it forms sodium salt of that acid so it basically absorbs you know the excess amount of you know Na that is produced as well as CO2 that is given out right so that is used in baking powder that is your baking powder difference with baking soda now here I mentioned it in a lot more detail okay so baking powder produces carbon dioxide on heating so it is used in cooking okay to make batter spongy okay now here is the reaction so if you only use baking soda you end up getting CO2 out then here is baking soda with tartaric acid for example you know which is used in tamarins so tamarins have tartaric acid you will find that there is carbon dioxide water and there is sodium tartaric which comes in right so baking powder is a mixture of baking soda and mildly edible acid that is the difference generally tartaric acid sometimes vinegar is also used vinegar is in fact quite often often used okay very much commonly used absence with baking soda okay and what the mixture of these two and another important thing this is generally used in powder form okay so it is just a mixture of baking soda with some powder of so I don't know if you have seen citric acid powder okay so which is your lemon powder very commonly found in any of the grocery stores so when you mix baking soda plus that is what your baking powder is formed you know whenever you heat baking powder you will find that again you know NaHCO3 is going to get decomposed so this is a good thing that happens is that any remaining Na that is there is absorbed by the acid and therefore it helps in making it more edible and not really remain unedible in consumption okay now we are talking about washing soda so what is washing soda in general so washing soda is your same sodium carbonate but with water of crystallization okay so we will again speak about water of crystallization in a few minutes I am going to define that for you and help you understand it but just to understand it here you know this Na2CO3 and 10H2O please do not forget writing 10H2O if you actually heat this back you know so you are having you have put in water you know and if you heat this back you actually end up getting Na2CO3 1H2O okay as the beginning one and further down you end up getting Na2CO3 only this is called as washing soda this is washing soda this is sodium carbonate monohydrate please note this is called as monohydrate and this is called as unhydrous this is called as unhydrous sodium carbonate or generally called as white sodium carbonate okay white sodium carbonate or unhydrous sodium carbonate what does the very word unhydrous mean something that has zero water in it has no water in it okay so this is sodium carbonate the preparation is you end up taking actually how do you prepare sodium carbonate you know you prepare this from so this is not exactly the preparation reaction okay this is actually the reaction of sodium carbonate but how do you prepare is you take NaHCO3 and you heat it okay you heat it very strongly once you heat it you end up getting Na2CO3 to begin with and then you add small amount of water at a controlled temperature small amount of water at a controlled temperature you end up getting washing soda okay 10 H2O so sometimes they also do what they do is they take 1 is to 10 mole ratio so automatically only 10 waters are there per sodium carbonate and your reaction stops at being washing soda and does not go beyond it okay so what are the uses so the uses are multiple so they definitely it is used in glass it is used in soap it is used in paper industry it is also used as a cleaning agent for domestic purposes very commonly used it is used in removal of hardness okay so washing soda is one of the ways in which temporary hardness can be removed temporary hardness in the last class we have seen a few glimpses on how can hardness be dealt with whether it is temporary or permanent okay so temporary hardness can definitely be removed by washing soda the structure of borax borax is B2O3 so borax powder and different compounds of boron basically right so all of these are very important components of washing soda okay now let's look at the next compound gypsum and plastrock paris we have come to the end a bit early but then we will try and do a few more questions on these okay now let's talk about you know water of crystallization you know I said Na2CO3 had water of crystallization and it is not just Na2CO3 a lot of molecules and compounds have water of crystallization with them okay so what is it it is the one that actually helps crystallize the core compound does that mean that the core compound cannot crystallize by itself sometimes no they cannot without water you cannot form crystals you know at times with water you definitely form better crystals so how does that really work I will show you a few molecular things as we find time okay so it is the fixed number of water molecules present in one formula unit in one formula unit of a salt so what do you mean by one formula unit if you take for example NaCl this is one formula unit you take Ki this is one formula unit you take H2SO4 one formula unit so you take one formula unit of COSO4 you find out how many water come along with it like in the crystal what is the ratio okay what is the ratio of the you know water against the molecules and from there you are able to figure out what is the water of crystallization that you have okay so COSO4 water of crystallization is about 5 okay with COSO4 there are multiple you know so you in fact in COSO4 also you know there are a few more for example there is one COSO4 with H2O okay so I don't know if you if you remember pure COSO4 is white in color okay this is light blue okay this is light blue and this is sky blue okay so this is you know very good bluish color very very nice color you know very pleasant color why H2O that coloration comes because of more of water being added to COSO4 now what happens to gypsum gypsum also contains the same water of crystallization and it is COSO4 twice of H2O whereas in when you heat this same gypsum you end up getting less amount of water of crystallization which is basically just half H2O you know this is called as POP plaster of Paris okay gypsum is actually naturally found in rocks called as dolomites so dolomites are basically natural minerals you know found in so there are a lot of these dolomite rocks you will find especially in North India okay somewhere around Punjab region and all of those region a lot of these dolomite rocks mostly made up of calcium substances okay now they would have gypsum a lot gypsum is like a normal mineral you know found in nature you heat up this gypsum you will find that you know you end up getting plaster of Paris POP so gypsum by itself is a bit soft okay if you heat it up you know it hardens up you know too good now there is another very common question that a lot of students ask sir why is it written as COSO4 half H2O why can't we write it as twice of COSO4 and H2O very good correct answer is absolutely right there is no problem in writing like this why do we write it like this is because we are not studying water here we are studying COSO4 so we will try and make one unit of COSO4 and then see how many units of water are clinging on to it and we realize that it is not even a single unit it is just half a unit which means for every two units of COSO4 I find one unit of water clinging around it and therefore I actually write COSO4 half H2O this is just a way of representation because we want to stress on COSO4 more and say that water is not that important right now we are studying COSO4 this is plaster of Paris now plaster of Paris there are multiple uses they are used in making toys making decorative materials smooth surfaces they are also used for example in making sculptures quite commonly used in making sculptures so how do you make sure that all of these how is plaster of Paris made now is plaster of Paris can it be brought back to gypsum yes it can be so the conversion POP to gypsum and otherwise one second the conversion of gypsum one second the conversion of gypsum to POP and POP to gypsum is quite possible so you heat this and you end up adding POP and you add water to it you end up adding gypsum back okay so these are the different ways now does gypsum have a direct implication no I am sorry gypsum does not have a direct application okay so that is something that that really works okay now so this actually covers all of our chapter notes but I am going to make I am going to give you enough time and we are going to actually solve some previous year problems and we will see how to write solutions for these okay so here is a question for all of you and I want you guys to attempt so I am going to look at everybody's answers now and we will see how many of you are actually able to really put an answer to this okay so and please try and use all the keywords in the modern answer in the answer that you are giving so that I can also show you these model answers and help you diagnose whether you are able to write the right answer or not okay so I have four questions with me and taking your time and feel free to write your right best answer that you can do this is a question just asked last last year okay 2019 identify the acid and base from which sodium chloride is obtained acid or and the base from which sodium chloride is obtained what type of salt is it when is it called rock salt how is rock salt formed what type of salt is it when is it called rock salt and how is rock salt formed see this is an entire answer absolutely information based question no concept here okay it is a complete I mean only the first part is concept and please note it is three marks you have to give in all the keywords you know please go ahead and shoot your answers I hope everybody is ready this question there are four parts to it first is identify the acid base second what type of salt is it I would recommend that you give all the answer in one one reply don't give part part reply because I will not be able to analyze with everyone of you being there so take your time write your answer you don't have to really make a fuss out of it you know just write your answer in four different points okay good answer which is the acid base used to form what type of salt is it when is it called rock salt and how is rock salt formed let's see okay so I have Vanisha answer you know guys I would just recommend even if you have answered earlier please make sure that you put everything in one answer and then write because I am going to show you a model answer and then we will be able to compare good Gurman Hita that's right you know but as I mentioned you know try to write all the four parts to it if you want to once again here it is what which type of salt is it when is it called rock salt and how is rock salt formed all of that is important so so can you give an example of sweet salts of what salts sweet salt sweet there are many you know for example you know your sugars fructose and sucrose you know if you just slightly you know put them so they have these H you know they have hydrogen they have aldehydes and ketones inside of them so that aldehydic H you know can be put in acid so your sugar when you put it in for example tartaric acid or vinegar acid you end up getting a acetate out of it sugar acetates or sugar tartarates like I showed you a few minutes ago you know for example your this is sodium tartarate right so this sodium tartarate actually is tamarind bitter bitter bitter in taste it's not even salty it's bitter in taste similarly when you get sugar acetates or sugar tartarates it's actually sweet in taste so you have your C6 you know your glucose C6 H2O6 you take out a few hydrogens out of it and you try and combine that with tartarates you end up getting a mixed taste sweet and so there are but you know it's not as sweet as the sugar that you would test taste so you see all of these tastes are basically a component of some ions in them if you get the right ions the taste can be simulated got your answer? yes sir now let's talk to yeah Sharvi has given the answer it is called rock salt when you upgraded to crystalline form very good Sharvi has mentioned this go cool I could see your answer but you know the rock salt part is missing Chris has mentioned rock salt part very good NOHHCl when evaporated very nice now guys I am going to give you the answer to this very nice VEDA, ETA everyone has mentioned now look I am going to give you the solution to this and please check how many of these points did you get right and I am going to mark the answers for this the model answer for this now so one mark is just for this now which type of a salt is this there is a half a mark the definition when it is rock salt and this is one mark so this entire thing acid and base is one mark which type of salt is half this is half when is it called half and how is the rock formed is another mark so if you have written HClNNH which I think everybody of you have got it you have received your one mark very clearly most of you got this neutral salt very correct so this half mark is also right half of you have not written one and these two parts when is it a rock salt rock salt when it is found in crystalline form very important keyword crystalline form like crystals it is then mined like we mined coal so that is rock salt so that is the one that is found in earth bear from earth people have written from sea evaporation no it has to be mined from earth when it is found in rocks in the rock form like you mined coal so that is the distilled salt is not a rock salt the second one is rock salt is formed by crystalline sodium chloride which is common salt ok the salt is dark in color because of impurities that are present in it because of you know early components that are present in it is typically formed by evaporation of salty water from sea water ok it can also be mined and it is also formed from salty water ok which contains dissolved Na plus and Cl minus ions ok so both of this has to be mentioned how is rock salt formed you know you evaporate and you also have dissolved Na plus Cl minus ions with of course you know some impurities that can be done I think Chris mentioned that you know Chris has mentioned that which is right which is ok ok now here we are ok Sharvi has also mentioned fantastic ok so all those who are able to do this very nice ok let's go to the next question now you know the pattern at all the points there is another three marker question you would need about a minimum of 4 to yeah this would have 4 points minimum ok so 2 ml of sodium hydroxide solution is added to few pieces of granulated zinc metal taken in a test tube when the contents are formed a gas evolves which is so there is a gas ok which is bubbled through a soap solution for testing soap solution write the equation of the chemical reaction involved so we need to write first thing is that we need to write the equation the second thing is name the gas so we need to identify the gas the last one is which will be evolved when the same metal reacts with dilute solution of a strong acid gas when it reacts with dilute solution of strong acid ok so these were three marks let me see yeah so the equation itself I am sure would be about one and a half marks gas would be about half a mark no hang on name the gas which is evolved when gas would be about this would be about one mark and this I think is about two marks let me just quickly check yeah that's right this is given for two marks and this is given for one mark correct yeah so take your time as I mentioned write the entire answer in one go please do not write in split parts because then we are not able to analyze it ok no answers yet yeah I have without answer Vanisha's answer I have good so that's nice Vanisha I think you are there Gurman ok yeah here it is yeah take your minute take your minute and try and write the answer completely I will comment on everybody's answer don't worry ok ok I guess that's good time let me see ok very nice so I have where was I I was at oh very nice I was at Vanisha's answer and then I have yeah Vanisha your answer is pretty there Tanishka's answer yeah Tanishka some more points I think you have mentioned it down below ok Sharvi's answer pretty much there Gurman ok Gurman has used the shortcut ok Veda is yeah ok then yeah Sprinter ok Sharvi fair enough Tanishka yeah the part is there Charanakash Zink reacts with only my wrong some use Zink it ok very nice Shanmukh I think you are there very good Veda fair enough ok very nice I think most of you have been able to do that one quick pointers ok people have not balanced this I understand probably you are typing therefore you are not balancing that's ok but important point Veda has balanced yeah and even I think Vanisha had also balanced Neha has not yet balanced but that's ok I know that is not an error on your part but important point that I am mentioning rest all should be rest all seems to be good great yeah now let's look at the model answer so I have also got your model answer for you here check this ok so the entire thing is important so what are the parts that needs to come out very clearly one second here we are ok so look solid aqueous balance narrow everything is important this entire thing will basically give you one and a half marks pop sound gives another half mark ok the test involved pop sound is going to give you half a mark ok that's what is there so I am going through the model answer and giving you this so there you get two marks and then this equation is important ok so this has been written in the so just naming the gas is not so see although they have asked this name the gas which will be evolved when some same metal reacts with added strong acid there is no need they have not asked you this equation but to your surprise they have given this in the model answer so if you don't write this you are going to lose half a mark ok and this is for another half a mark ok so so one and a half for this reaction half a mark for pop sound they have given half a mark for writing the equation although that is not asked please note there is no way written they have only said name the gas which will be evolved with that reaction they have not said state the reaction you will end up losing half a mark unfortunately so that's how cbc is so you better be ready better be proactive at your end and make sure that you are addressing the all the points that they are desiring ok now we have two more questions to go so I am going to give it slightly faster ok now that you are well versed please attempt this in the next two minutes we don't have much time also left so there is this two marker it's a two marker question try and attempt in your best I am going to keep this screen for a few seconds and then we will be looking at the solution let's see ok so what is observed when 2 ml of dilute hydrochloric acid is added to 1 gram ok 2 ml 1 gram of sodium carbonate dilute hydrochloric acid taken in a clean dry test tube write chemical equation for the reaction now please note they have said what is observed this is going to carry one mark and then writing chemical equation is going to carry one mark so you better be now I understand that you might not be able to type the entire thing I take it I know it but try and give your best is all I am saying try and give your best is all I am saying ok ok so if you have read this question well I hope if you have taken down I have already said what is observed has to be written pretty well writing the chemical equation has to be written pretty well clearly it's a two marker question asked last year just last year this question was asked let me see how many of you are able to write this ok now very nice so I am going to go from the bottom Beda has written it she has balanced it also she has written gas ok I just said something about this particular test I said something about this particular test sodium carbonate ok tricky one ok ok so Charvi has written that's right Charvi fantastic ok good balancing I think you would do in the paper Veda balancing is done that is also done nice Gurman very well ok yeah fair enough yeah that's right Madhumita fantastic yeah Meda has also been able to try has been able to write this very nice so excellent when excess CO2 is added very good very good yeah fantastic so Gokul has also mentioned this Gokul Veda Charvi ok excellent ok yeah fair enough Tanishka ok Gurman Charanakash as I mentioned the entire writing Madhumita very nice very good I think everybody is able to do this now ok so I am going to show you this model answer and I am going to make a few comments which are important for understanding this ok please note please make a note of this ok yeah so let me show you the answer first ok here's the model answer oh oh sorry yeah here's the model answer on diluting HCL with Na2CO3 ok which they which is what we are looking at so HCL was put in Na2CO3 in a clean a brisk effervescence ok so this effervescence word has been used in model answer please note effervescence word has been used in model answers ok CO2 released is not is not sufficient CO2 gas is released not sufficient bubbling is an alternative word that they have given here ok so as I am seeing at the model answer effervescence slash bubbling ok slash bubbling gas released also they have mentioned gas they have mentioned so probably you will get this but CO2 is of little significance at this point you know so this is this is for one mark ok just the observation due to evolution of CO2 gas and then the reaction twice of HCL here it has to be mentioned aqueous Na2CO3 aqueous I was not able to type in here therefore I have left that ok ends up giving H2O liquid CO2 arrow gaseous all of that will fetch you another one mark ok so brisk effervescence bubbling of gas gas released all of these all of these is important and then writing the chemical reaction twice HCL Na2CO3 H2O CO2 balancing balancing is another important bit H2O CO2 are already balanced NaCl NaCl should be added here ok NaCl twice of NaCl twice of NaCl plus H2O plus CO2 all of that and NaCl will be aqueous so all of this will get you your complete two marks ok ok now let's go to the last question that I wanted to show you today ok let's do a quick last one do I have one I don't ok right good I do have one ok so I'm going to give you one more let me see ok so give me one quick minute and I'm going to give you one quick question hang on guys give me a minute yeah here's a question for you I'm going to dictate it ok guys please note and try and write the answer for this this is a question that was asked in 2018 itself again ok three marker three marker I'm going to dictate this question please write an answer to this the pH of a salt used to make testy and crispy pakoras ok so common in the word used so guys who have not who doesn't know pakoras might have missed out on this question the pH of a salt used to make testy and crispy pakoras is 1414 identify the salt and write a chemical equation for its formation identify the salt and write a chemical equation for its formation that is the first one the second one is list is two uses list it's two uses I'm going to repeat one more time pH of a salt to make testy and crispy pakoras is 1414 pH is given to us identify the salt and write a chemical equation for its formation ok so I'm going to reshare the screen and probably I'm going to reshare the screen give me a second why can I not share because I stopped sharing here's the screen I'm going to write that question for you and then I'm going to give the model answer also here itself ok ok so pH to make pakoras ok is 14 of a salt ok pH of a salt is given to you they have asked you identify the salt identify the salt let me see if I can put it on the screen for you yeah I am able to put it on the screen oh come on yeah here it is ok try and answer this list it's two uses yeah it's a two marker so take your time and put all the points that are important for this ok identify the salt and write a chemical equation for its formation list it's two uses let's see how many if you are able to do that now ok I hope everybody has got this ok uses very good Gurman see that is very important see he is the first I think I don't know if anyone has given it earlier or not so Gurman and Gokul has also given now very nice guys Mehta is also given very good ok so without giving the equation you know you will not get your full mark without giving the equation not getting full mark yeah so Veda Vanisha has also given now ok very good now everybody is trying is giving it out ok that is very important yeah very good Charan Akash excellent so Shanmukh has also given it it is also balanced in some ways ok fair enough ok yeah a lot of a lot of answers varying a bit ok from each other but I think most of you have been there ok most of you have been there so I am going to give you the model answer for this ok so please note the important valuable points the first thing that they have said in the model answer the salt is yeah so they have given it as NaHCO3 ok NaHCO3 please note it is not Na2CO3 for God's sake it is not Na2CO3 it is NaHCO3 has been given here ok and they have also given this reaction NaHCO3 ok heating is giving out Na2CO3 plus H2O plus CO2 ok twice twice so this has been released ok this has been given ok yeah so this is mentioned and write a chemical equation for its formation so this is mentioned for use now for formation they have used this NaCl equation ok so if you have given Na2 I can see a lot of you have been giving ok yeah so that's what and a lot of you have actually written everything around yeah so Shanmukh's reaction is right which I can see also correct with Char-V and all the other so you have been able to write this reaction of formation pretty well yeah pH 14 is I know the pH is slightly misleading guys I understand but it is NaHCO3 that they have mentioned therefore I am rechecking and giving you the one that has been mentioned here ok so here they have clearly mentioned ok so giving you one more time ok NaHCO3 is stands for half a mark ok they have also written here the equation where twice of NaHCO3 ends up giving Na2CO3 plus H2O plus CO2 ok and this is this leads to crispiness ok this is this leads to crispiness this is what has been mentioned so I guess but you know they have not given strangely they have not given any mark here but I assume that you know probably this is another half a mark ok or else just NaHCO3 would lead you to one mark but this has been mentioned in the answer so better be clear about it now the second thing it's formation reaction you know preparation or formation that reaction has been written as NaCl plus NH3 plus H2O plus CO2 ends up forming NaHCO3 plus NaH4Cl ok NaHCO3 plus NH4Cl is it balanced is it balanced OH plus H2O is it no not it balanced yeah I'm sorry yeah yeah Mehta I know it's right you know so Mehta I connect to you but I can't help you know I mean that's what has been there that's why I have always been saying especially in chemistry and biology this is the case ok it is not the case physics and for example maths you know in maths and physics you would get point-to-point answers but here they have ok here they have mentioned so it's better to really use it Charvi that's not the reaction for preparation I don't I yeah so Vanisha's reaction is right NaCl3 plus Na2CO3 plus NH4Cl but I'm going to go get you back to the model one you know so for example where we just wrote this yeah NaCl plus H2O plus CO2 gives NH4Cl plus NaHCO3 that's the one that's all we need ok this reaction I hope everybody is able to get this ok this reaction has been asked for a mark ok so this is what you have to reproduce for another mark ok look at the reaction you know small things here and there can take you completely off the grid ok and list two of its uses I think this everybody has got it right I'm going to give you four or five uses to this so the first use of course is using in making baking powder or in baking purely you know making food fluffy you know CO2 making dove rice all of that ok second very much used in you know making cleansing cleansing action also ok it is very much used in cleansing action ok used as antacids ok used in textiles ok textiles also so all of this you know multiple of this any two is useful antacids is very good baking is very good I think everybody remember these two ok good so great you know Sagar unfortunately you there is no choice so you need to do chemistry as well ok yeah fantastic very nice good so good session you know I like being on these sessions I don't know how you guys feel a quick comment you know does this really help you guys you know how is how is it really happening how does it all go for you guys how these sessions go can you quickly put in are they helping you do you feel do you feel you know kind of really I mean something that adds value to you ok so shares is enjoying it when he says enjoying it but you know guys you don't have to be just goody-goody about it all the time you know you can very clearly please mention in fact I would like to hear anything that we can improve upon you know because that helps everyone to assimilate things ok anything that you feel anything that you feel that we can add more to that can actually help you guys last class of the decade yes Sharon that is right anyone who feels that there is anything that we can add to what we have been doing that you know that can make yes you know whether that feature will come in soon so the comment box will be floating at my end in fact on our zooms it always loads we have much more power but because now we are using this feature it will come up soon ok yeah missing you man I hope we will meet up soon good yeah that's nice Prisha yeah make yeah ok Prisha I know that audio quality Sharon you know mostly it it might be a function of your internet also yeah you know not really always function in here but Veda yes of course the entire next year we are going to have classes the very next week we will have classes so ok ok good in fact you know guys you know the good part about this is that right now I'm in Pune actually you know and I'm able to connect to all of you and I think it is pretty seamless you know so in spite of me not really being there you know you we are able to meet and talk ok pretty nicely so it's like 30 at the time still working but I'm so happy that I'm able to close the class session with you guys for this year which is a really nice thing you know so pretty pretty pretty nice to see all of you meet all of you know all of you I know a few of those mischievous faces and names at the same time a few glad ones so good to have all of you together ok ok very nice guys so thank you so much I know that you know you guys will keep on being so yes yeah yeah so you guys have a good time wherever you are bye bye