 okay already all set okay yes as it is they are all new in new to this online teaching that's why it's little difficult for teachers ever okay let's go we are starting our first question and I'm going to start and it has related to acid base and unsolved okay fine first question reads like consider the following statement whether water act sorry acts as an asset or as base depends on other speech present second option is every liquid is either an asset or a base which of this statement is are correct ABCD4 options are in front of you one only two only both one and two neither one nor two okay think about the cases think about the cases can water act as acid can water act as base can any liquid be the acid or base every liquid are either acid or base can you see when you have to think like that yes board is there on the screen 510523 okay 59 students have already solved I think 7 more students 5 to 7 students have not answered okay fine so but whether water act as an asset or base depends on other species present yes and every liquid is an asset base is acid or base okay fine so your time sir oh my only 18 students have given right answer fine we will try to understand see questions questions seems very easy but you people have made mistake means we need to discuss the questions properly yes okay see the question was like this I'm sharing my I'm sharing this I think all up to burn this thing okay see yes okay whether water can act as acid or base depend on other species present yes it's it's true let's see you're talking about ammonia ammonium and reacts with water you know what it will what it will going to give okay ammonium hydroxide you know what it's going to give ammonium hydroxide okay you know okay fine so what actually happens or let's say if I give you one more example let's say H2SO4 H2SO4 reacts with reacts with water okay H2O what it is going to give you it will give you a hydronium ion S3O plus plus SO4 2- now you will ask sir how what is hydronium ion hydronium ion is nothing but you can take it like this H plus plus H2O gives H3O plus and you know that if something accepts proton something accepts proton what we call that accepting of proton is acid or base tell me students accepting of proton is acid or base okay first tell me yes except accepting proton is nothing but base which base there are three theories Bronsted and Lory base Arrhenius base and and Lewis base so we don't need to think about that but you can yes you can understand that it is nothing but Bronsted and Lory base are no problem but you know that something which accepts proton is base you know this thing so no need to know about the name but I think all of you know that something which accepts proton is base so this is nothing but Bronsted and Lory base okay this is Bronsted and Lory base now you will ask sir okay this is fine but where water will act as an acid where you think water will act as an acid so what you can say you know water can also act as an acid because when water is there and it let's say it is react with CO2 okay not CO2 you can take some other examples here you know if you have a OH- ion or let's say I would I would say I will give you this example NA okay NA NA is there sodium or any OH is there and when it reacts with water what you are going to get what you are going to get any OH-ech was okay or or just a minute which example can I give you to show yes this is an base and for acid you can also think let's say I'm writing this reaction a very easy reaction you may think sir what is it but generally we say this reaction is like H3O plus plus OH- you know this is of one kind of reaction where water and water gives H plus and OH- some people have doubts are why how water gives H plus and OH- for that for them I have written this equation water is acting as an acid and water itself acting as a base so you are going to get one is losing H plus then you will get H3O plus when it accepts and when one water molecule loses H plus yes this is a reaction which because many people have doubt sir how water forms H plus and OH- okay water always give H plus and OH- okay how it gives water and water if you if you explain the reaction water will react with water molecules will form H3O plus like this understood sir but water is a product of neutralization yet it's not neutral yes yes definitely okay fine very good question I would say it is very good question see it doesn't matter water is a neutral no doubt it is a neutral but it can behave as acid they said that in general pH is 7 only but it can behave as an acid or as an base depends on the situation it can behave as an acid or as an base depending on the situation understood okay nature of see question is very clear whether water act as an acid or base depend on species present yes it can act as an acid or act as an base okay it can be a proton donor water can be a proton donor okay if it is acting as a proton donor it can act as a base any doubt it can act as a base where acid when it is a proton donor when it gives OH- it can act as a base okay students if anyone has any doubt please ask okay okay this will any OH act was only this this example does not fit in this case that's why I did not explain with this that's why I took this example here it is giving it it is just not just a equus solution is forming yes acid is proton donor and water is you know okay very very good question you know water according to Bronsted and Lory something which gives proton is an acid something which except proton something which except proton is base if you go to Bronsted and Lory it is giving proton see it is giving proton so according to that it is Bronsted and Lory acid students did you understand this okay can you speak if anyone has any doubt can you please speak okay next is every liquid is either every liquid is either either acid or base no no there are many liquids which are not acid NaCl which is not acid okay this is not an acid many people have one more doubt I want to tell you for them you know when NH4 plus reacts when NH4 agent as reacts with water, then can you tell me what will be the product? Anyone? what is the product? NH4 plus this reaction with three action what is the product? Very good,with What you are going to get that is my question with ammonium hydroxide you are going to get Ammonium hydroxide along with that you will get H3O plus or I would write H plus H plus in this form water is acting as a acid See water is acting as a acid and in this reaction Water is acting as a base see here Water is acting as a base in this reaction That is nothing but this reaction So you can have both of these reaction possible water is acting as a base in this reaction water is acting as a acid Neutral solution cannot act as a yes. Yes see Water behaves as an acid and base actually acid bases are theories Neutral solution can act as an acid can act as an base depending on the reactant Present in the reaction Whatever reactant present based on that we will decide every liquid is either an acid or base. It's not am I clear to all of you Okay, fine moving to the next question Moving to the next question Okay Next question is this So all questions are very thoughtful. You should think about the question first then answer The hydronium ion is the strongest and said that can exist in aqueous solution Mixing concentrated acid and base with water is highly exothermic reaction. Which of the following is are correct? Hydronium ion few minutes back we discussed as 3 of us is the strongest acid that can exist in aqueous solution Mixing concentrated acid or base with water is highly exothermic Know that it can be him as an asset human it's like we discussed how it will Be maybe an aqueous solution you need to decide and mixing the reaction It is exothermic on end of coming sorry Maria. It is end of coming mixing concentrated acid and bases with water is highly end of coming, okay So the answers are like this So, let's see 26 students have written the answer and 26 have given the right answer. That is a okay. Let's have a discussion. Okay, fine So just a minute. We will discuss the second question. It is like this Yes Mixing concentrated acid and highly end of coming. No, it is exothermic B is definitely not the answer if you talk about a hydro in your mind is the strongest asset Yes, it is the strongest asset while you people made mistake in this. I have no idea answer is a only Please ask if anyone has any doubt then I'll explain in Yes, it's Okay, fine. I read it as a comic. Okay, my mistake. I read it as a comic But you could have read it as end of coming. I can apologize for that. But now is it clear answer is a You must have by mistake. I read it as exo Yes, any doubt So you should trust on your eyes Not on what I'm saying. I may say wrong while you are doing Christians I may try to confuse but in previous question. I did not say deliberately by mistake I told exothermic Okay, why is S3O plus my dear S3O plus is a highly strongest or is the strongest acid. Why? because you know Whenever there is a acid, you you can understand it like that H plus does not exist like H plus, you know, H plus is very reactive So when it reacts with water it from hydronium ion Now this is acting as an acid. That's why we always write like this, you know, normal H2SO code I want to tell you very very important thing, which you may not know, you know, if I say H2SO4 gas H2SO4 gas if you have put a pH paper pH paper that is blue pH paper. What will be the color of blue pH paper? If you put HCl gas Blue pH paper will be converted into red. Yes Blue will convert it into red. Yes Yes or no No, it will not convert into red because you have taken H2SO4 gas H2SO4 gas cannot convert cannot show the pH change because it is not having Protonated ion. It is not having H plus. So what happens when you put H2SO4 in water In water then you get H3O plus that hydronium ion to hydronium ion you are going to get plus sulphate ion you will get This is the reason behind the change in color of the pH indicator Exactly. Equal solution OH minus ion is the strongest base Okay, forget about the organic chemistry, but it is the base among yes OH minus is the strongest base for you understood later in class 12 we will see some different things also but For your knowledge OH minus is the strongest H3O plus is the strongest acid understood moving to the next question Okay, leader board says that Anirudh is leading. Okay. Good Anirudh INR 10 Oh no, Arya Rao NTSRNR very good Arya keep it up Okay, moving to the next question be ready for that Consider the foreign statement these things contain SNOic acid Okay, think and answer the white MMR in our truth is made up of calcium sulphate Acidic nature of substances due to formation of X plus ion in the solution Which of the following statement is are correct? Okay, capital A capital B capital C capital D you have to pick small a you can see that small a small v are the options even in question itself. Okay These same white MMR acidic nature See students by this time you should not get full wins 100 percent I should get correct answer You I'm getting the zigzag curve I've given fine past two questions. I think the ratio of the people who has done wrong is If I take average the people who have done questions wrong are more than people who have done it, right? So you have to change that average Okay, last 10 seconds. Oh my god. Okay, see go how many of you have done it, right? Oh my god, 33 students have done right. Okay, it's fine. But still many of you have done wrong these thing is nothing but formic acid and MMR in the truth is nothing but Which okay, those are written see as the answer. Please tell me the answer Why the second was wrong calcium phosphate was wrong by our calcium pulpit was wrong by Yeah, that has a calcium phosphate by this thing. I told the right answer Calcium phosphate is the answer Yes, okay And few minutes back we discussed the acid acid is showing is acidic property just because of its Hydrogen ion Okay, let's see whether Who is leading now? No means also in the line. Oh No means leading very good. No me moving to the next question Get ready for that Okay, Incognito. Please Relame you or tell me who are you? Here's the following statement solution of sodium hydrogen carbonate is alkaline in nature Alkaline nature sodium hydrogen carbonate used in fire extinguisher Which are the following statement is our correct? Okay, I think people are thinking what is the purpose If anyone has any doubt, please ask not related to question any other thing you have to ask Okay, sodium hydrogen carbonate This question is again a good question. And I want to tell you one point really with the help of this question 67 have already answered 69 Okay Okay, fine So answer for this question is 34 you have you have answered it right dear student sodium hydrogen carbonate is nothing but NAHCO3 I want to tell you one point with the help of this question. That's why I gave this question. So the point is The point which I wanted to explain in this question is What is an anchomer? So I will tell you not now One day I will tell you you can't understand it now. Okay, I think nature of substance. Uh, sorry next question. Yes Okay, one minute Yes, here it is the question. Okay, so question is NAHCO3 I want to tell you one thing in case of NAHCO3 you should understand all of you It is sodium hydrogen carbonate and you have a sodium hydrogen carbonate I why I gave you this question. It is an alkaline nature always remember one thing salt First you write understand the salt is formed by which acid and which base Which acid and which base Can you write which acid and which base? From which the salt has formed acid is acid is H2CO3 and base is base is NAOH strong base weak acid strong base weak acid salt So this is a salt of strong base weak acid Salt of strong base weak acid are always alkaline are always alkaline in basic media in in aqueous solution Understood one question. I wanted to ask all of you. Can you tell me what is the nature of? of of Fp ovate whole thrice Okay, fine. Not Fp ovate whole thrice. Let's say I asked you Fp SO4 What is the nature of this salt? Is it acidic or basic? It is acidic very good. It is formed by Fp ovate whole twice and that's 2 SO4 a strong acid weak base So it is acidic in nature Okay salt is having an acidic nature in aqueous solution Okay in alkaline in nature in aqueous solution. They have a right solution Okay for the sodium hydrogen carbonate is used in a fire extinguisher. This is a very very important point That's why I gave this question many people have doubts on how fire extinguisher Can you tell me which gas is released in fire extinguisher? Which gas is there? Can anyone tell me? CO2 actually what happens there is any HCO3 Sodium hydrogen carbonate reacts with H2 SO4 As some reaction happens which type of reaction you will tell me after I'll write the reaction It is nothing but any 2 SO4 forms Because H2O forms plus CO2. Which type of reaction is this? Neutralization very good Neutralization reaction because few minutes back I told you this is nothing but this is base It is base kind of base see here. I have written it is alkaline So this CO2 released is used in the fire extinguisher now you people may have doubts or how it is acting as a fire extinguisher So how how these gases are reacting for that? I have already opened one folder for you You know this is a fire extinguisher Here you have a knob. Here you have a bottle In this bottle you have a sulfuric acid When you open the knob the sulfuric acid is reacting with sodium hydrogen carbonate Earlier this knob is remain closed Earlier this knob remain closed Okay, I can't write on this So knob remain closed But as if you want to extinguish fire you open the knob Your sulfuric acid reacts with sodium hydrogen carbonate which is on the container and CO2 release CO2 release from this and it out Okay, fine, then it's good Moving to the next question We ready for that And next question. Okay first see who is leading. I think Anushka is leading Let's see who is leading now Good Anushka Okay, Pranam was the fastest Consider the following statement when the bare basis react with metal along with revolution of hydrogen gas A salt is formed which has a positive ion composed of the metal and oxygen Oh my god, very long statement I may have to read it again Okay, but I'm not reading. Second is acid and basic solutions in water conduct electricity Because they have produced hydrogen and hydroxide around respectively Okay, good Acid and basis neutralize each other to form corresponding salts and water Which statement is our correct Very easy question Once again Okay, how many of you have already answered? 47 Fine Okay, okay, there are many but don't write the answer Okay So easy question only so I'm expecting I'm expecting 70 percent students will give a right answer in this case, but see What data we are going to get after this 20 seconds Why 70 percent? Okay Because I thought for first question. I thought it will be 70 percent only 40 percent student made it right. Okay, let's see the answer Oh 28 Okay, more than it's a 50 more than 50 percent student have done this wrong. Surya, did you understand why I gave this? Surya Okay, fine Okay, fine. So now we are going to discuss this question Okay, just give me one second students Okay, it is question number this five Question number five is Very easy question When the base reacts with metal my dear student base does not give the hydrogen gas Not base acid reacts with hydrogen acid reacts with metal give hydrogen gas Not base They have written base react with matter along with evolution of hydrogen gas. No It does not give generally base do not react with matter only Generally bases do not react at all So by reading this much only I will say, okay, it's wrong Base are this much base does not give hydrogen Then these statements acidic and basic solution conducts electricity because they are produced hydrogen and hydroxide. I have respect to you Yes, it's correct They conduct electricity because of that only you need ion to conduct electricity only two things can conduct ion and electron So ion are present Yes acid and bases neutralize each other to form cells. So answer is bc. So answer is b and it out Okay, very good question My dear student it is for the amphoteric oxides not for all Zinc plus NaOH there are three oxides in last class. I also told you pb al all those things Okay When zinc zinc react with NaOH Yes, you will get the sodium zincate Yes, but it is not a generalized statement It is not a generalized statement that you can make it for everything for all the bases You can't make understood any doubt You can't generalize it for these three metals. You can see Those are the just exceptions Okay, any other doubt No doubts fine moving to the next question So fine now. I'm expecting. Okay. Who is going to lead now arian good arian The bleaching powder. Okay. Please note the timing. You will have only 60 seconds So do it fast. We have only 60 seconds Bleaching powder Prepared by what? Okay, as it's own. Well, how it can take answer by its own Okay, so answer for this question is bleaching powder Okay, let's see how many of you know about bleaching powder Okay, 32 students have answered it right very good students. So bleaching powder is caos whole twice class cl2 Okay, and formula of bleaching powder is cao cl2 many people Okay for One thing I want to why I gave you this question. There was some purpose of giving this The purpose was to tell you the reaction not to just mug up. I wanted to tell you don't just mug up the reactions There is one thing I what what I felt that people just learn the reactions So I want how to predict the reaction in this case See calcium is there How to predict calcium is there Calcium hydroxide Okay, it is ca plus 2 Oh, it's minus plus cl2 Okay, it is a accurate solution Okay, you know one thing when cl2 reacts with water what it gives It gives you a cocl. This is what we have in a chlorine water When people say that is a chlorinated water that is an h o cl and cl minus H o cl and h cl you get actually H o cl and h cl Now, this is a chlorinated water. So definitely you are going to get o cl minus from this I'm just explaining you how you get the bleaching powder o cl minus So when I'm writing aqueous plus cl2 you can directly write like h o cl h o cl and h cl Just like just I'm writing all the anions present All the anions present here and cations present. So your bleaching powder is ca o cl2 You know, what is ca o cl2? It is ca o Ca o and o cl minus For ca o cl minus and cl minus Sorry, ca o cl minus and cl minus. So cl minus come from this h cl part This part o cl minus comes from this part And ca plus 2 comes from calcium only This part Understood Okay, this is just I wanted to tell you how you no need to mug up the reaction try to understand what all cations and anions present which form the product Okay, moving to the next question Okay, Sneha is leading Let's see. Oh, no Aryan is still leading So today chick Okay, you people are leading CHK people are leading today Sir is hydrogen form No hydrogen does not form in the previous reaction Column 1 and column 2 are given and 2 SO4, NaOx, CaSO4, CuSO4, Na2CO3, NaNO2 So many options are in front of you You have to think what will be the change in change in the color of indicators 23 students have answered so far You know in last class also we discussed something about the indicators if you remember This thing I discussed in last last center mark And I told you what is the color change based on the compounds 60 have answered still there are many students who need to answer Please answer it fast otherwise. Okay, everyone has voted very good Coming to the answer part Oh my god Still less than 50 percent is the Correct answer. Okay, fine. So again, it is a very easy question We are moving to the seventh question I just wanted to tell you like how to do this question H2SO4, pH will be blue to red That's what blue to red Na2CO3 few minutes back. I told you Na2CO3 is nothing but basic salt Na2CO3 is a basic salt. So just give me one minute Na2CO3 is a basic salt Okay, so it is basic If it is a basic it will change the pH. It will have the same properties like a NaOH only So NaOH and Na2CO3 behaves like same only So, you know if you see the answer B answer A PRT is for B and PRT is for the D also because both behave same. Okay, how PRT it must turn Red to blue because it is NaOH RS pin of clean is pink in basic medium T is pH paper turns blue in basic medium. All three things are right Litmus pH paper everything. Okay now copper sulphate copper sulphate is neutral one Okay, so now see Again, if you remember, it's not just neutral H2SO it is found by sulphate SO4 Sulphate is it is a it is a salt of CO which whole twice and H2SO4 a strong acid weak base So a strong acid weak base means same like acid it will behave same like acid So here you have a QS here you will also have QS and last is NaNO3 that is neutral It is a neutral that's why When it is a neutral you won't have any color change or you will have a green in this So answer is E. Tell me if anyone has any doubt. Okay, fine So you could have asked me students if you have any doubt in the questions you could have asked me Okay, moving to the next question Okay, see the leaderboard first. What is the leaderboard? I think still CHK students are leading very good Okay, moving to the next question acid rain is caused due to caused due to rich all oxides You have only 53 seconds left Acid rain caused due to rich all oxides. Okay, there is one more Oxides and rich all gases like H2O2 You must have learned acid rain and I think you have been learning about acid rain from last 2-3 years Okay, let's see the answer 51 of you have answered very good CO2, NaO2 and NaO2 all three are Causing acid rain Okay, so CO2, NaO2 and NaO2 all three are there Arian Tandon Is leading very good Arian. Okay moving to the next question Which of the following is acidic salt? acidic salt sodium hydrogen carbonate sodium bisulfate potassium chloride potassium bisulfite and sodium carbonate Please think about the question properly and then answer Which of the following are the acidic salts? sodium bisulfate potassium chloride potassium bisulfite sodium carbonate So question is very easy But you may not get full marks in this also Okay, fine. Let's see the answer Only 30 students have done right now you people are thinking why It is like this Okay, see Okay, so the question was Very easy Okay, not this ninth number question was that And the question was see you have to understand one thing acidic salts and basic salts are those salts which have a hydrogen ion Hydrogen ion and OH-ion respectively sodium bisulfite You need to write the formula of sodium bisulfite. What is the formula of sodium bisulfite? NaH sulfite they have given NaH SO3. So if I write the sodium bisulfite Uh, just a minute Okay, it is like H SO3. NaH SO3 means hydrogen ion is there which is uh causing it is an acidic salt Okay, and the next one is the one more hydrogen Carbonate was there by sulfite and by carbonate by means NaH CO3 So both are the acidic soil. I don't know why it's not opening Just a minute One minute students Okay, so is it clear now if I write NaH One minute one minute student. I'm showing you Just a minute Okay, fine. Uh, I'll I'll show it you in one minute. So by carbonate. What is the answer for this? Yes Now NaH NaH SO3 NaH By sulfite they have given formula is NaH SO4 NaH SO4 So it is having a hydrogen ion. That's why it's an acidic salt acidic salt potassium chloride KCl not acidic salt potassium bisulfite potassium is K bisulfite is H SO3 minus is bisulfite So K H SO3 it is again a acidic salt acidic salt And the last one is sodium carbonate Na2 CO3. It is not acidic salt nor neither a basic salt understood any doubt You know, so what is the identification? Let's say How to say when something is acidic and basic if you see somewhere hydroxide somewhere hydroxide then it is acidic salt If I give you this compound Cu CO3 dot Cu OH whole twice Can you tell me which type of salt is this acidic or basic? Which type of salt is this it is called as basic copper carbonate, you know basic copper carbonate It is a basic salt. Why because it has OH in that I think you understood what I want to say here moving to the next question Okay next is Please read the question properly And then answer you have only 60 seconds to answer this question Select one of that does not give CO2 when treated with dilute S2 SO4 Does not give CO2 when treated with dilute S2 SO4 Marble limestone lime baking soda You have to work out. It's not like you simply get the answer They have asked does not give limestone marble baking soda Baking soda related question we have already done in today's class. Okay fine next time off Baking soda is nothing but NaHCO3 And the answer for this question is C very good lime CAO, CAO when reacts with S2 SO4 Gives you CAO SO4 But rest all will give you carbon dioxide because there is a product S2 S2 will come in all the cases Okay, tell me CAO will not get CO2 Arpan and limestone both are same CACO3 CACO3 when reacts with S2 SO4 CACO3 when reacts with S2 SO4 It will give you S2 CO3 S2 CO3 reacts into S4 and CO2 any doubt Students we have any doubt in this question. Please ask Could I explain one by reaction? Okay, wait. So here you have four four four compounds marble CACO3 Marble and COCO3 both are same Okay, so you can write like this CACO3 But CACO3 when react with S2 SO4 Gives you double displacement reaction H2 CO3 will form but in last class I told you whenever S2 CO3 forms in compound You don't write like this. You write H2O plus CO2. Please mute your mic plus CA SO4 So these are the products Okay, next is limestone same thing limestone is CACO3 only Next is lime lime is CAO And reacts with S2 SO4 Gives you CA SO4 You are going to get CA SO4. Now next is baking soda baking soda is NAHCO3 reacts with H2 SO4 Gives you double displacement NA2 SO4 Plus H2O Plus CO2 Understood If anyone has any doubt, please ask Okay, fine Next question is Meghana, did you understand? Meghana asked that Okay, so Aryan is leading and Sneha just after him Okay, see next question Okay, please read the question carefully and answer What is the concentration of solution with 10 gram of calcium in 1000 meter tube of water in PPM Parts per million Very easy question Okay, how many of you have no idea how what to do? Why It's like think parts per million. I'm I'm Giving you a hint You have to find out the concentration parts per million Concentration is always a term used for solutes If solute is more we say concentration is more so Parts per million is to think you will get the answer Okay So nine more second fine answer is Okay Answer is B and most of you have done this question wrong. Okay. Let's discuss this and it is very easy question See nothing you have to understand only one thing in this question. What is that? What is that thing here? You have to we have asked the parts per million. Yes Parts per million means if 10 grams of calcium 10 grams of calcium is there 10 grams of calcium Okay Is there in thousand meter cube of water? Meter cube of water. Can you tell me how much? Calcium is there. Okay, since they have asked the concentration Do you know how much mass of calcium is? Atomic mass of calcium Atomic mass of calcium is what anyone? Forty very good Implies moles of calcium are moles of calcium How many moles you must have learned how many moles of calcium? 10 by 40 very good These moles are present in thousand meter cube But we have asked We have asked per million So in one meter cube in one meter cube Moles of calcium are moles of calcium Is 10 by 40 divided by 1000 In thousand meter cube One by 40 sorry not 10 by 40 in 2000 Into 10 power 6 You will get answer as 250 Understood Any doubt? Very good Moving to the next question Just you need to okay. There is in next question. Also you need this concept. Okay of concentration Let's see how many of you have done this right Why I took the concentration things because in pH calculation you need that So first we will Go through the concentration properly Next time we will learn the pH calculation also In your class by the time you will get your teacher will teach you How much sodium is there in a solution with 10 kg of solvent and concentration for molar? Concentration for molar Concentration is nothing but Moles by volume those who don't know Concentration is nothing but moles by volume Meghana, I will show you that question After I finish all these questions. Please wait Okay Concentration is nothing but moles divided by volume of solution So for molar is given to you Moles divided by volume you need to do Again who has no idea what to do for them Concentration is moles divided by volume Moles of solute Divide by volume of solution Yes, Aryan ask your doubt. What is brownstone glory? It is a base and acid. It's a theory for acid and bases So brownstone and jury says that h plus donor are acids H plus acceptor are bases Okay, fine. So Answer of this question is 24 students have done this right. It is again a very easy question Just I will take one minute to explain this. So question reads like Concentration is given to you concentration is nothing but moles by volume. So moles of sodium moles of sodium divide by volume Okay, so volume is volume. I don't know But it is given that 10 kg of solvent density is given. So moles of sodium is okay. This is given as 4 Okay, they have asked you how much sodium so moles of sodium is nothing but 4 into volume of solution volume of solution Now you will ask that what is volume of solution they have given density density is what density is mass of solvent divided by volume of solvent volume of solvent mass of solvent given is what 10 kg So density is 5 equals to 10 kg divided by volume So volume we are going to get as 0.5 Volume is nothing but 0.5 meter cube 0.5 meter. No, sorry 2 meter cube. Sorry. Sorry. Sorry volume is nothing but 2 meter cube is the volume is 2 meter cube. Please substitute this value. So moles of I will write this as 4 implies moles of sodium is 4 into 2 meter cube But you need to convert into okay fine. You need to answer in grams So meter cube when you solve you will get mass in kg divided with the thousand you will get the answer Any doubt student any doubt yes if anyone has any doubt please ask Okay, so you will do like this here. You can calculate the moles of sodium once you calculate moles of sodium What you need to do multiply it with 23 23 into 8 184 gram is the answer 23 into 8 184 gram Moving to the next question Okay, are we are just last question then I'll explain that again those who want to go they can go I would explain that question again. Please wait for one more minute. Okay. I'll explain that uh question again Okay, last question the solution now listen to this see this question properly five molar solution moles of caCl2 divided by volume of solution And they have given 27.75 percent calcium chloride by mass By mass they have given 25 percent by mass means Okay, this you also learned in class nine percentage mass by mass You know by mass means mass of solute divided by mass of solution Into 100 mass of solute divided by mass of solution into 100 is the percentage mass by mass Okay, last 18 seconds. Okay, let's see that Okay, only 14 students have done this right. Let's see this question also Okay, now what to do? Thus, it's again a very easy question Christian was not tough to answer see But you need little calculation in this five molar solution is given to you. Please understand it I will explain all the three questions five molar solution means five equals to moles of caCl2 moles of caCl2 divided by volume of caCl2 Volume of caCl2 solution now you will ask her how to calculate moles and volume. So see moles. Okay, the given data is Given data is 27.75 Percentage mass by by mass they have given that is nothing but mass of caCl2 divided by mass of solution This is given to you This is given to you. Okay. Now how to calculate Answer they have given moles of caCl2. Can you write moles in terms of mass? What is the mass of caCl2 molecular mass of caCl2 student please tell me molecular mass of caCl2 Molecular mass of caCl2 is triple one. Okay, fine. So can I write like this? Can I write like this? uh It is mass of caCl2 mass of caCl2 divided by triple one that is the moles of caCl2 Now I'm keeping denominator as it is volume of caCl2 And it out. This is equation one and this is equation two What you need you need density of solution density is what? mass of solution divided by volume of solution divided by volume of solution Okay, so what you need to write only this thing mass see there are two equations mass of solution you need it is there mass volume of solution volume of solution is you need it is there mass of caCl2 will get cancelled out if you divide one equation by two And by taking the ratio you will get the answer students did you understand? It's very easy answer will be two gram per centimeter cube What I have done I have written the equations three equations Then whatever I needed I have found it like mass of solution is here And volume of solution is obtained by This is volume of solution volume of solution is obtained by equation number one divide these two Equation you will get the density understood Yes, it's long. I know that you need to write three equation one two and three Using the above two equation you need to calculate density density is molar concentration is moles of caCl2 divided by volume Moles of you know that moles formula moles is nothing but mass divided by molar mass mass divided by molar mass So molar mass of caCl2 is triple one Mass is mass of caCl2 is You don't know so you actually you don't need also because in these two equation What we can write divide one by two Divide one by two you will get answer Yes, definitely the answer which you are going to get is not in centimeter cube You need to convert it into centimeter cube You will get answer is in liter And thousand centimeter cube is one liter. So you have to convert that Yes, yes Okay, fine. I'll explain the two questions first. I will announce the result Then I'll those who have doubt they can stay back Okay, so that's all for today. Let's see who is the winner and the winner of this Okay, arian tundan and ps chk very good arian congratulations Okay, fine. Thank you one. Yes. I am explaining the past to the question which we discussed someone told me I'll show the questions So I'm showing you the last two questions. So that's one. Okay in this question Okay, you have How much podium is there in the solution with 10 kg of solvent? So I'll tell you who to have doubt today explain Okay, fine arian and big enough. So how much sodium is there in solution of 10 kg of solvent? So see moles of sodium divide by volume of sodium is nothing but concentration That is nothing but given to you as four I have written four So implies moles of sodium is nothing but four into volume of sodium volume of solution Now you need to calculate volume of solution. What is given data to you? Moles of sodium is given density is given to you density is five So what I've written five equals to 10 that is the mass of solvent divided by volume of solvent By this way volume you got two meter cube as a volume any doubt Volume you got two meter cube once you get the volume as two meter cube you put here You will get moles of sodium as eight Once you get moles of sodium as eight you multiply it with 23 Understood And 23 into 8 is nothing but 184 you will get Okay, there is one more question. You have doubt in that previous one. I'll show that also This this Yes, this one PPM one I think Anyone has doubt in this? Please see 10 gram calcium in 1000 meter cube atomic mass of sodium is 40 moles of calcium is 10 by 40 10 by 40 moles are there in 1000 meter cube since they have asked in ppm ppm means parts per million parts per million Means in in million thing in million thing how many moles are there so 10 000 In 10 in 1000 meter cube Moles are 10 by 40 in In one million part It is 250 Did you understand? Okay, I will share the worksheet Okay, any other doubt any other doubt 13th question 13th question is this one Yes, you need to divide one equation by another. Okay, what you need see The question is is very easy a five molar one minute Just a minute students one minute Just one second Okay, a five molar solution is given. Okay. Tell me which step you have doubt Five molar solution is given and it is 27.5 things Okay, now they have asked you See what is the how you get the answer for this question molar concentration of 27.75 for cacl to by mass Percentage by mass you must have learnt in class 9 Percentage by mass is nothing but mass of solution mass of solute divided by mass of solution mass of solution I will do one thing in my next class. I will take the full center mark on these type of question So mass of solute or divide by mass of solution So you have mass of solute mass of solution that is 27.75 and five is nothing but moles of kacl solute volume of solution Moles of solute is nothing but mass divided by molar mass Divide it divided by volume. This is all long questions. I understand that mass of solute Divide by triple one divide by volume of cacl two once you do that Once you do that you get two equation one and two just divide one equation with two You will get the density of solution because in density you need mass of solution mass of okay, don't do two one by two do two by one You will get exactly the density to two by one Did you understand alisha? Do you want me to solve this whole thing? Okay, see I'll show you in one more other page Okay, see I'll show you on some other page Just give me one second. I think it was 13 question. Yes Yes, now see this question they have given Five molar five so what I will write Moles, okay, I'll write each by step by step five is nothing but moles Divide by volume Okay, that is five molar moles is Moles is nothing but I am assuming that assume Assume cacl to mass as x So what I will write mass of x divide by triple being is the molar mass divide by volume Volume I don't know the volume Okay, now I'm using the second equation 27.75 is nothing but mass of solution divided by divided by Sorry mass of not solution mass of solute mass of solute divide by mass of solution Into 100 mass of solute is mass of solute is What I have assumed it as x x divided by mass of solution is mass of solution Okay You will write it as a mass of solution. You don't know so you will write mass of solution mass of solution Okay into 100 That is 27.75. Now you may have see there is one more thing given They have given you 27.75. So can I say or what I need? I need density density is what mass of solution divided by volume of solution Volume of solution Okay, now see are you listening to me all of you those who are present anyone who is present Okay, fine. So see density is mass of solution divide by volume of solution density Now tell me mass of solution you will get from here You need to remove this x. What to do? Tell me can I do the equation 2 divide by 1 what you are going to get do that If I do equation 2 it is nothing but Equation 2 divide by 1 is nothing but see 27.75 Is equals to x divided by mass of solution mass of solution into 100 This is numerator part divided by denominator part. I am writing with the red pen so that you can understand. So what is that? 5 Now it is in the denominator part. What I can write Into x Yes, this is divided by triple 1 into volume Yes or no 2 by 1 you will do like this you will get that x will get cancel out you got mass of solution divided by volume of solution Okay reverse it Yes, yes reverse it. What you are going to get implies 5 by 27.75 Is equals to I have reversed this 5 by 27.75 is nothing but density Nothing but density Because mass by solution divide by 100. Please tell what is the answer? 500 divide by 27 point something what you are going to get What you are going to get do this? Did you understand what I have done? Did you understand? Yes, what you are going to get by this? It's 18 something one minute. Have they calculated mass of he is here to write The moulin con solution or is 27.75 percent cacl to buy mass. What is the density of solution? What is the density of solution? So Just see have we done everything right? I think cacl to mass also. It's right Okay, just one minute mass of solution volume of solution 27.7 percent mass The density is given mass of solution divided by volume of solution and mass of okay five molar solution Is five moles divided by volume moles is even mass of solute divided by triple one And volume of solution. So you get x divided by triple one into v Okay, that is five Now here you have 27.7 x divide by mass of solution in 200 So you do 27.75 divided by five is equals to x by m x into this divided by x x into Triple one into v Is it correct? Yes Now what you are going to get x will get cancelled out So mass by volume is nothing but density Is nothing but Uh mass by volume it will give you 111 into 100 divided by Mass by volume 111 into 100 divided by 27.75 Into five do this student what you are getting triple one 110 Okay, I for I forgot this triple one. Sorry students. We have not considered this triple one in the calculation Did you understand? We did not calculate. We did not Consider this I forgot to put one triple one here. You people didn't tell me Okay, you will get 2000 when you get 2000, but it is in centimeter cube you will get in liter So you need to convert into that Understood it is little lengthy question, but when you divide it When you divide it earlier, I told you the right thing when you divide it you will directly get simplified form Understood any doubt Any doubt students What yes, that's okay fine. So if anyone has any not please ask otherwise We can leave and you can have your dinner Okay students. Thank you I hope you understood something Let's remember the few things concentration density And molecular mass. Okay. Thank you