 Okay, can you hear me guys? Good evening. Okay, so today's topic is as Surya asked and one more student has asked. Today we are going to discuss acid based reactions, introduction part and few chemical reactions as well. So how are you all of you? Are you good? Yes. This is our second, I think second class, second centre march. So how is your other subjects in centre march? Is it very interesting? Yes? Very good. So again, what I want to say to all of you is first read the question properly and then answer, though you are going to see so many options and you will think like, okay, many of your friends has answered, but it doesn't mean that you answer without reading options properly. No displacement reactions, don't worry. Okay, it doesn't mention it's good, but it mentioned in my screen, fine, no problem, but still you should answer it after reading the options properly. Okay, no problem Varsha, don't worry if acid based reactions are very easy. I will tell you the basic concepts if you were not able to answer the questions. Don't worry, we are going to learn in this class. Okay, Varsha, is it clear? It's a very introduction part. You know that what is acid, what is base. If you know the simple idea, if you have a simple idea about that, it's fine. Don't worry, we will discuss acid and bases in detail in today's class. Whatever doubt you have, please don't hesitate to ask. I'm going to solve all of your, I'm going to answer all of your doubts. So if you have any doubt, please let me know. Okay, yes, neutralization reactions, acid bases give the neutralization reactions. Okay, there are few questions related to pH. So I think all of you have a little bit idea of pH, Varsha? No, Meghna, you don't have any idea of pH. Okay, what is the pH of an acid? No calculation, no calculation. How come how come I can give you the questions related to calculation if you, if we don't teach you calculation? Yes, very good. You should have a little bit idea of pH. That's it. Yes, pH for acids are less than seven. pH for bases are, tell me pH of bases are more than seven and seven to 14. Very good. Have you, do you have this much idea as Varsha has written yes? And there is one more girl who said she has not, she doesn't have any idea. Meghna, Meghna, do you have this much idea? Yes, that's it. This much only required. So now the question is what are the strong acid, what are the weak acid like that you should remember based on the, based on that we will say pH will be very high for very basic solution, very less for highly acidic solution. Yes or no? Do you agree with me? Very good. Very good. We'll wait for a few more minutes for the friends to come. Then we will start two important things. Okay. Okay. And today we will learn one new type of reaction also as we discussed something in the, something related to reversible reaction. Do you remember we discussed something in CH1 and Centum R1 for chemistry, we discussed something about the reversible reaction. Do you remember students? That's it. Do you remember something? Yes, very good. We discussed something about the reversible reaction. Do you remember if you don't remember, don't worry. Again, it is a kind of a revision for you. We will revise it. We will solve the question and I know that most of you are going to answer it correctly and you are going to enjoy also. So just try to revise, try to remember what were all reversible reactions we discussed in last class in your last Centum R. Try to remember that so that you can take advantage of that. Think about the last class, what we discussed in the reversible reaction. Okay. So students, can you hear me? Okay, fine. Now we are going to start in one minute. Okay. Are you ready? Have you revised what we discussed in last class? Because kitchen may come related to that. Anyone is facing any issue in joining? No issues? Good. Okay. Okay. Bye. Bye. I am not going to give you any, any kitchen related to calculation of pH because we have not discussed pH. In your school also we have not, in your centum classes also we have not discussed pH calculation. Don't worry. I am not going to ask anything related to pH calculation. But you should have a little bit idea of pH. You should have a little bit idea of acid. How acid behaves? How base behaves? There are few important points which I will tell you during the process itself. Yes, yes. It is just intro to pH. Don't worry. Okay. Fine. So I think now we should start. It's like still one more student has come. Okay. Please let me know if anyone is facing any issue. Otherwise I am starting. No issues? Okay. Fine. So I think all of you are ready to start the quiz. Still one more student has come now. Surya, do it fast. Okay. So now Surya, have you done? Okay. Fine. One more student has joined. Surya, are you that only? Who has just now joined? Yes. Everyone ready? Okay. Good. So now I am starting. It's a total 69. One more student has joined. And now the quiz starts now. The first question on your screen is this. Which reaction is reversible? Now if you remember I told you just revise it quickly. It is a reversible reaction you have to mark. There are four reactions given to you. Which reaction is reversible? Maybe you are answering wrong answer. Think properly. All are copper. All are copper only. Copper. Okay. I will try my best to confuse you. Okay. So don't get confused. You should have your, you should have confidence in answering the question. Okay. So, okay. All of you are able to see it properly. I hope all of you can see it on your screen. Yes. Very good. Very good. If you face any problem, please let me know. Okay. One more student has to answer. But still you have seven seconds. Please answer it fast. Oh, this is time up. And the answer is. Answer for this question is D. Okay. Many of you have done this question wrong. So fine. You know if you, if I take you to the question, what a question was which among them were the reactions of, sorry, which of them is the reversible reaction? So reversible reaction you have to tell in that. And if you see the question was this, which reaction is reversible? So reversible reaction, you know copper plus ZnSO4 displacement reactions are not reversible reactions. Always remember. Next is copper oxide plus H2SO4. Acid-base reactions are generally not reversible reactions. Generally they are not. Okay. They are fast reactions. So copper sulphate and bannets are a strong acid definitely not reversible. Copper oxide plus hydrogen. Again a displacement reaction not reversible fully convert into copper and water. This reaction, the last reaction is reversible. Okay. I think most, can you see my screen because many of you are saying you are not able to see my screen? Are you able to see? Very good. I think all of you can see my screen. Okay. Anyone has any doubt? Last reaction is reversible reaction. Anyone has any doubt? Please say yes. If you have any doubt, please write Y. No need to write N. No need to write Y. There is a one Y. Aditya. Aditya, what doubt you have? The question is which is among the reversible reaction. Now if you see, the question is very easy. If you see here, you have copper plus zinc sulphate. First reaction is displacement reaction. Displacements are non-reversible. Okay. Second one is kind of acid base reaction. It is a neutralization reaction. You may ask how it is a neutralization for your information. For your information I want to tell you neutralization reaction. Can you use a color combination because pen is not very clearly visible over cell phone. Over my PC. Over my cell phone it is not. Okay. Fine. A bit thicker version of the same might work. Yes. Is it visible now? Yeah. Very clean. Okay. Second is the neutralization reaction. Okay. In neutralization reaction you can see because copper oxide is. Okay. If I ask you one question how many of you can answer copper oxide is a basic in nature or acidic in nature? I want to know from you. Is it basic or acidic? Basic. Basic or acidic. Tell me. Okay. It is basic. Very good. You know metallic oxides are basic in nature. Just put this thing in your mind and keep it there only because you are going to use this concept in later in few questions which I am going to show you. So metallic oxides are basic in nature. When it is basic and you have H2SO4 that is acidic. What is going to form? Acid base reaction. It is nothing but neutralization. Yes. Neutralization reaction. You are going to have. Okay. I hope this answers the question. Third one is again a displacement reaction. Third is also displacement. I will write here third reaction is again displacement reaction. Displacement reactions are also fast non-reversible reaction. And fourth one is reversible reaction. I hope you understood this. Any doubt? Just write why if you have any doubt. Okay. Good. So we are moving to the next question. Get ready for that. Second question is in front of you. So okay. So you can see the leaderboard now. Okay. Fine. So Aniket is leading. Okay. So next question is in front of you. Okay. Just a minute. Just one second. You have forgot to take the cursor. Take the cursor. You are still using your writing thingy. No sir. I am not using writing. This is cursor only sir. That arrow is not swing. Just use the keyboard arrow if at all it is like that. I am using keyboard arrow only. Should I refresh it? So the arrow is bottom left corner. Bottom left corner. Nothing is wrong there. No Bravad. I guess this is your other cursor. Sir only one. Okay. Okay. I have removed that thing also. Lighting pad. Still it is on this. Okay. Just one minute students. Okay. Fine. I will take you to the next. That's the PBT. Just that's the question number one PBT. It's not getting. Your pen is selected. Bravad your pen is selected. Go to the cursor. Go back to one note and all. Your pen is selected still. It is the cursor only. Okay. Just some. Just some. Just normal cursor. Okay. Got it? No. There was the next button. There only down. There you went. Yeah. There. Go like. Okay. Fine. Okay. Okay. Next question is the diagram shows that the change in change from an anhydrous salt to its hydrated form. You have an anhydrous salt and one in hydrated. So it is which type of which statement is correct. So now this is a very good question. It is related to the one principle which I told you in class in which I am teaching but you should able to answer this question. Which statement is correct when you make an anhydrous salt and you are converting into hydrated one or if you say the other way around hydrated salt is converted into anhydrous what will happen just think about when you have a copper sulphate hydrated copper sulphate how you can make an anhydrous copper salt. What is the role of water in that? I think most of you got the answer but still few I have not answered yet the diagram shows the change from an anhydrous salt to a hydrated form. What is the answer for this? Okay. Students there are there are still students many students who have not answered please answer it fast. I think oh my God times up now we will see what will happen and how many of you have answered it correctly. Oh so it's a equal weight. Okay few of you have answered properly and few of you have not now we are going to see how to make this this how to solve this question. Okay. So if you see the question is question is this is that it is in front of you. So question says how you can make. Okay the question is this you have to make and a forward reaction is given to you when anhydrous salt is given to you and hydrated one. Okay I want to tell you one thing if you remember when you heat a hydrated copper sulphate what will happen? Will it become anhydrous because when you heat something when you heat something it become anhydrous for to remove water you need to heat the salt. So anhydrated salt become anhydrous when you heat the salt yes. So can I say that forward reaction if you see the forward reaction is nothing but if you see the forward reaction it is in the forward direction yes. This is in the reverse and that's above is the forward you want which is the correct statement forward reaction require heat and water is it correct statement forward required heat and water no because if you have anhydrous salt you heat it it become more anhydrous it will not become hydrated so first option is wrong. Forward reaction require water only now here I want to tell you very important thing forward reaction requires water only how to how to explain this point. So I am taking one example is in front of you you have a copper sulphate hydrated 5x2O okay and you are heating this copper sulphate what you are going to get please write the product I want to know from you if you heat copper sulphate what you are going to get write the product write the product very good copper sulphate anhydrous plus water will be removed water will get removed this is anhydrous salt okay now if this is anhydrous salt now I am going to ask you very very easy question you know it's like there is no chemistry but it's a completely simple question if you have a if you are very thirsty okay if you are very thirsty and if someone if you are thirsty let's say I am drawing your your so if if you are very thirsty and you want and someone gives you water okay let's say this is your you and someone gives you water are you going to drink water or not are you going to drink it yes or no yes let's say you have an anhydrous the word itself says you clearly that anhydrous copper sulphate is nothing but someone has taken water from it if you give water to it will it going to form copper sulphate dot 5x2O yes or no yes or no very good so now if you remember the previous if you remember the future if you give water to this compound reaction will go in forward direction or in backward direction if you give water to copper sulphate that is not hydrated that is not hydrated and hydrous copper sulphate you give water where the reaction will go copper sulphate see anhydrous means this point this copper sulphate if you give for this reaction it goes in forward direction but in question but if I ask in this reaction when it is an equilibrium where the reaction will go it goes in backward direction that's the very important point so what can I say this is also explained by the the principle called as Le Chatelier principle Le Chatelier principle says that we will discuss that Le Chatelier principle later on as of now we don't require but always remember whenever there is a hydrated salt and you heat it you heat it it become anhydrous when you have anhydrous salt you give water to it it become hydrated is it clear to all of you yes it came in Camon same type of question was there in the Camon I think all of you understood this point yes if anyone has any doubt write N if anyone has any doubt write N no very good so we are moving to the next question get ready for that and it is in front of you so first see the leaderboard ok so Surya is leading good good Surya now we are going to see the next question so I think you understood this point this this point may be used in next question or question after that so be ready for that ok so next question is in front of you try to first understand the question and then attempt when green iron to sulphate is retained it turns white a colorless liquid is produced when the liquid is put back into white solid it changes back to green oh my god what type of reaction take place and what is the name of liquid use the concept which we have discussed so far and the concept which you learnt in chapter one chemical reactions and equation there is a very beautiful example which we take there that is the iron sulphate which iron sulphate is green in color there is its name is also very very important so if you remember the name you can be able to answer this question also green color iron sulphate very important compound ok I think 73 students have answered and last 2 seconds and time is up ok let's see how many of you got it correct 36 students only 36 have given the right answer rest of them rest of you have given wrong ok let's discuss this question again it's a very very easy question and very important important also let's discuss this you know you know have you ever heard about f e s o 4 dot 7 h 2 have you ever heard about the name of ok what is very good aditya has written name of this also that is a green withdrawal ok it is a very very important compound it is green in color and iron sulphate it is green in color when you heat it again the same thing which we discussed in copper sulphate can you tell me what will happen I am not going to write now you will tell me what will happen when you heat someone which is already which has already drunk too much water what will happen if you heat that thing very good it will lose all the water f e s o 4 will form with 7 h 2 ok directly 7 h 2 will not go first 6 will go and then later one will go no problem we will write like this ok what is the color of this it was also given in the question what is color of this it is also given white in color or some people write make color less in it is a color less or white in color ok white color thing you got now they ask very easy question if you read the question they said if f e s o 4 when you heat when you ok let me take you the question on to the question the question says the question says if you have f e s o 4 ok this one yes when a green iron 2 sulphate is heated so it is very clear that f e s o 4 dot 7 h 2 o and then what is given it turns white and our color less liquid is produced color less liquid can anyone tell me what is that color less liquid anyone color less liquid is what water very good and the liquid back into a white solid is changes back to green ok it is the same thing like a thirsty person if you give water to that it will drink it quickly similarly the f e s o 4 and hydras will drink it very fast and you will get this ok now type of reaction is it a redox reaction many of you have written answer be to clarify this concept I just want to tell you how come you can write it is a redox reaction it is not at all redox reaction if you see is it a redox no nothing is oxidized nothing is getting reduced it is just a kind of decomposition reaction water is getting going out from the compound if you go with the oxidation number also f e plus 2 sulphur plus 6 oxygen minus 2 f e plus 2 sulphur plus 6 oxygen minus 2 hydrogen plus 1 hydrogen plus 1 oxygen minus 2 oxygen minus 2 nothing got changed is it clear to all of you then only I will move to the next question ok if anyone has any doubt write n don't know need to write y write n if you have doubt you can speak also you can ask if you have some doubt related to this question here and there if you want to ask something no ok fine we are going to the next question and the next question is in front of you first we will go through the leaderboard let's see whether Surya is leading or someone has someone else's has taken his place ok I think Surya is still no yes Surya is leading good good ok keep it up it's not end yet we have so many you people have so many opportunities to lead now next question is this now we are going to discuss something about acid and bases which statements are property of an acid reacts with ammonium sulphate to form ammonia ok just don't write fine quickly just write the reaction I will help you write the reaction try to understand whether the option one is right or wrong right when you write it then only you will get to know whether what is the answer react with ammonium sulphate to form ammonia ok just try just check it if it forms then second is turns red litmus blue turns red litmus blue will it going to turn red litmus blue I don't know ok fine we'll see red litmus blue litmus I know it is some it is extracted from some plant I that much I know ok fine it's time up ok let's see how many of you got the correct and oh my god you have all of you so fine we need to discuss this question answer is D ok let's discuss this question where you people made the mistake I want to see that ok if you see the question was this question the question given to you was what is the reaction when ammonium nitrate ok try to understand this question reaction of ammonium sulphate to form ammonia ammonium sulphate to form ammonia you need to check ok how to check that ammonium sulphate to ammonia ok now see ammonium sulphate to ammonia this is the question ammonium sulphate is ok fine tell me formula of ammonium sulphate how many of you know the formula of ammonium sulphate first I want to see that if you know the formula you can able to answer also ammonium sulphate right the reaction NH4 oh my god ammonium sulphate wrong wrong everyone is writing wrong yes momita has written right ok the problem is you people don't know ammonium sulphate ammonium is NH4 plus sulphate is SO4 2 minus if you see if you say ok I want to make compound out of these two you know very one method very good method that is known as crisscross to charge of sulphate will come down ammonium charge will come here and the formula is NH4 whole twice SO4 this is ammonium sulphate what they are saying ammonium sulphate to form ammonia ok they have given some acid let's take some acid I am my favorite acid is HCl I think that your favorite is also HCl yes or no is it your favorite ok fine so it is HCl no no ok no problem so what will happen can anyone tell me what will be the product what will be the product what is the product ok H2SO4 with ok fine fine ok it is nothing but a kind of double displacement reaction you must have learned this thing when a salt react with acid double displacement take place Cl minus is here H plus is here for product is NH4 will go and this form compound with chloride and you will get H2SO4 something like that though this reaction is not very favorable but fine if I take HCl there are possibilities that it will form ok H2SO4 if you are taking HCl yes understood now they are saying that ammonia is liberated can you see some ammonia do you see some ammonia liberating do you see some ammonia liberating no if anyone see please let me know there is no ammonia yes ok so there is no ammonia in this so what does this mean if there is no ammonia means option B is not option A is not our answer means this is not correct and turns red litmus blue no acid turns blue litmus red base turns red litmus blue did you understand this yes ok along with this I want to tell you a very very interesting point here let's say in place of acid you take some base you take some base NaOH ok so now if you see this is the if you take NaOH what will happen if you take ammonium salt and NaOH any idea ammonium salt plus NaOH no reaction always remember whenever ammonium salt is heated whenever ammonium salt is heated with base it will give you am mere this fact to remember it this fact you remember whenever ammonium salt is heated with base any equally it will give you ammonia always remember this thing ammonia you will get out of this so what you are going to get along with that if there is ammonia what what you are going to get along with that ammonia and water and and Na2 SO4. Always remember is it clear now what is what is the thing to remember ammonium salt ammonium salt on heating on heating with alkali with alkali always give ammonia just remember this fact because this fact will be used in one of the question okay now I am any doubt in this question any doubt in this question no okay fine so we are moving to the next question next question is in front of you see the leaderboard what is happening okay what type of reaction is that that is again double displacement my dear double displacement reaction only okay so please mute your mic what lesson I give him the last chance okay I'll see to it I can get the IP address not a problem okay fine okay next question get ready for that oh fine which property is not characteristic of base think think think one question we did for acid now it is for base please think and answer I'm telling you questions are very good options are even better than the question so don't don't ignore any option please read all the options first and then answer yes please read all the options then answer please read all the options okay 65 people have answered good which property is not a characteristic of base okay fine time's up and answer is a most of you got it right no problem we will discuss this question as well don't worry if you didn't get so Christian next question is this only that if you have okay so okay now Christian says that which of the properties not a characteristic of base it react with carbonate to form carbon dioxide now try to understand it reacts with carbonate to form carbon dioxide no how if you see okay carbonate to carbon dioxide base let's let's I if I if let's say I don't know this reaction if I don't know reaction then what I am going to do can you tell me if I don't know the reaction what should I do I will write the reaction I will try to write the reaction and then see any carbonate you take which is your favorite carbonate tell me tell me your favorite carbonate tell any of your favorite carbonate then I will tell you the reaction okay calcium carbonate fine it is a favorite carbonate you know the your plasma is the made up of calcium carbonate only if you have a calcium carbonate okay now you have some in calcium carbonate you are putting what you're going to put you are going to put some base base okay which is a favorite base which is a favorite base quickly tell me okay if you put a base NaOH what what you are going to get what you're going to get you only tell me I'm not going to tell you because I know that you people have good enough idea like what will be the product very good if you balance the reaction it is two times and you know that it is a kind of double displacement Na2CO3 plus plus plus what very good plus CaOH whole twice very good I will write plus CaOH whole twice okay now the question arises is there any liberation of CO2 no not at all it is not liberating CO2 okay what kind of reaction is this who can answer what kind of reaction is this is it a neutralization reaction my question is this okay double displacement is fine can I say it is a kind of neutralization reaction no okay Na2CO3 is forming CaOH whole twice is forming okay fine there is no precipitate my dear there is no precipitate no acid okay anyone else okay fine so it is a kind of double displacement it is not a precipitate there is no precipitate it is also soluble it is also kind of soluble only understood yes so there is no gas liberation also okay fine we are moving to the next it reacts with acid to form salt yes you know that that is the answer it reacts with acid okay so they have asked which is not the characteristic A is the answer it reacts with ammonium salt to form ammonia few minutes back only I told you base with ammonia give base with ammonium salt give ammonia it turns universal indicator blue how many of you know universal indicator how many of you know all of you universal indicator universal indicator give all the colors when you have it's a having a range of color so when it is a base it will give you blue color is it clear yes it is a kind of example one example is that also yes litmus also but you will say the means there is a wide range of colors you will see in the universal indicator we will come to that in one more question then I will explain that in detail first I want to know from you only one more question related to in universal indicator is about to come don't worry coming to the next question and first see oh he is leading okay fine moving to the next I think you can read the question I will read it for you a sting from insect x has a ph of six and a sting from insect y has a ph of eight the table shows the ph of substances fine acid as hydrochloric acid one ph sodium hydrogen carbonate eight ph sodium hydroxide 14 and vinegar five don't don't get scared by seeing the size of question it's a very very easy very easy question just use your brain just think what happens to you when you eat too much when you eat too much what happens to you now I've given you enough heat enough hint you can answer now properly using this concept okay fine I'm reading it options are x is hydrochloric acid y is sodium hydroxide this is a option b option sodium hydrogen carbonate and vinegar c option sodium hydroxide and hydrochloric acid d option vinegar and sodium hydrogen carbonate any any doubt and the ph givens are hydrochloric acid one sodium hydrogen carbonate eight sodium hydroxide 14 vinegar five okay let's see what will happen in this okay it's a mix no problem don't get worried I have said questions like this only so that you get confused don't worry but before going to this class you should learn the concept that's the intention behind the questions if you are not able to learn when there is a there is no point of attempting these types of question question is very easy hydrochloric acid is one okay one thing I want to ask from all of you which is the stronger acid HCl or okay which is the strongest idea of acid among all these four among all this forth which is the strongest base among all this four which is the strongest base among all this four very good HCl is the answer for acid which is the strongest base very good now can I say that okay if I ask you which is the acid but not as stronger than HCl, which is the acid but not as stronger as HCl. Yes, yes, yes, yes, yes, very good. Vinegar, vinegar is something which is, which is acidic because pH is less than 7. Few minutes back I told you before the start of the session, pH less than 7 is the acidic only. Which substance are used to treat the two stings? Okay, if you remember I gave you a hint. When you eat too much, what happens? What happens to you when you eat too much? What happens to you? Let's say you have your, your mom has made some favorite, your favorite dish. Yes, no water loss. It is the sleep. Okay, don't write the side effects. Okay, basically it is acidity which, which so you have acidity in that case. What you take in that case, you know, yes, to neutralize the excess acid form in your stomach. Same thing when there is some, some B sting, you know, that is an acid. So when B sting, having acid in that, so in, in such cases you put, what you put some base to neutralize it. Okay, there are two stings. Okay, they have given which substance are used to treat two stings. Okay, so, and it is given the sting from the insect asses pH 6, means acidic, sting is acidic in nature. So what you are going to use for X, you will use for X what you are going to use, base. Okay, then don't take the sodium hydroxide, it is highly basic pH 14. Don't, don't try to take it that at all. You know, base, very high base will, is very corrosive. Don't take this much, but, but you need base, but it doesn't mean that you will take very concentrated base, you will kill yourself. So you take some base, but with B, which having a less strength. So answer would be sodium hydrogen carbonate. Okay. Okay, then what is the answer for Y? Y sting is having which nature? Y sting having which nature? Yes, you can go to that also. Very good, Aryan Tandon. Very good. You can also write pH of acid plus pH of base equals to, because you want to neutralize pH of acid, but pH of base equals, base equals to 14. You can also go through that as well. So pH of acid plus base should neutralize. Okay. So you can go in that way also, but for the Y, what is the answer? Vinegar you are going to take. Okay. Can't you take HCl? Yes, actually it was very easy. That's what I told you. Don't get scared by seeing the length of question. Now my question is, why you don't take HCl in this case? You can take HCl also now, if some B sting is there and you can, why you don't take, sorry, why you don't take HCl in this case? You could take HCl also, but it is highly acidic. You know pH is one. It is very acidic. You know in your labs also, no lab instructor will allow you to do this. They will not allow you to touch that. Okay. Fine. Moving to the next question. Get ready for next. It's a very easy question. Don't get scared by seeing the length of question. Sneha Chikbanwara is, I think Chikbanwara, yes. Oh, Ankur is leading. Fine. I hope this is not Ankur, sir. Okay. Good. So next is, next question is in front of you. Very big question. Don't get scared at all. I have said questions like this only, but if you know the concept of acid and waste, you can solve in seconds. Can't see. Okay. I will read the question for you. Three liquids PQ and R are, three liquids PQ, R are added to a mixture of hydrochloric acid and a universal solution. The following observation are made. P, the color of the indicator turns purple. Q, the color of indicator does not change. R, there is a effervescence and the indicator turns blue. What are PQ and R? Okay. Sodium, I am reading the option A. Sodium carbonate solution. Water and sodium hydroxide solution PQR respectively. In B option, sodium hydroxide. Water, sodium carbonate solution PQR respectively. C, water, sodium carbonate solution, sodium hydroxide solution. And D, water, sodium hydroxide and sodium carbonate solution. Just these three solutions are in front of you okay I have read the question three three liquids P2 and RR added to a mixture of hydrochloric acid and universal indicator is also present there P the color of the indicator turns purple P on adding P turns purple on adding Q no change on adding R effervescence with and the indicator turns blue think you got enough time okay many of you have answered it correctly no problem those who have not got this okay the question was big lengthy we understand that okay so fine now what how to solve this question so the question is this three liquids P2 RN this this this okay try to understand when you have a universal indicator and hydrochloric acid okay and indicator you know that when it turns red it is an acid when it turns blue it is a it is a base now the question is there are two cases the doubt must your if you have doubt the doubt must arise in these two cases turn purple and turn blue only in these two cases you may have doubt okay so how to resolve that doubt okay try to understand there are two cases one is NaOH is given to you and in another case what you have one is NaOH and other is one is NaOH and other is sodium carbonate solution sodium carbonate is Na2CO3 okay I want to tell you one thing is it acidic or basic tell me is it acidic or basic okay not NaHCO3 sodium carbonate that is sodium hydrogen carbonate is NaHCO3 Na2CO3 in front of you it is basic why why it is basic anyone okay mildly basic why anyone metal carbonate okay I want to tell you okay always remember metal carbonates are slightly basic in nature because that is the secret now I'm going to tell you the secret why it is basic it is formed by the strong base and weak acid that's why it is basic NaOH and Na2CO3 make this Na2CO3 that's why it is a weakly basic because it is a strong acid a strong base strong base it is a weak acid hope you understood this yes okay so next question so what is the answer you know answer is B sodium hydroxide solution P turns purple and sodium carbonate is weakly basic it turns blue when it is highly basic when it is a highly basic what you say it turns into purple color blue get intensified and form purple is it clear okay we are moving to the next question get ready for that okay rest other questions are little easy for you so now who is leading let's see who is leading now oh uncle sir is leading is it uncle some okay fine yes there is effervescence okay I will I will talk about that first finish this question the table shows the pH of solution W X Y and Z there are W X Y and Z pH are given pH for W is 7 X is 9 Y is 2 Z is 5 that is 5 okay so now universal indicator is added to each solution which role shows the color of each solution after indicator is added okay what happened you are not able to join okay just put that number 6 7 6 2 1 refresh it maybe you will be able to join then okay yes yes quickly W 7 X 9 Y 2 Z 5 you have to tell the chain color of the universal indicator very easy question you just have to tell the universal indicator color chain in all these cases last 20 seconds okay now you have nine more seconds universal indicator color chain what will happen okay time's up now it is again a very easy question now see you people are meeting a very silly mistake in this question also so question says the color change so I want to tell you whenever you have a universal indicator in universal indicator when it is a highly acidic highly acidic is a red so you know which is the highly sorry highly acidic is a red which is the highly acidic why why is the highly acidic so simply you can get the answer as B because red is only in that option okay now but we will not go with the this type of tricks we will learn the concept so red is the highly acidic and when you have a pH highest pH is for X that is a highly basic and when it is highly basic you have a blue color highly basic blue less basic more acidic red W is green because it is a neutral it's a kind of neutral solution and if it is a less acidic less acidic it will be orange color it is the nature of a universal indicator did you understand these are the this question is completely based on the color change of the indicator at different pH yes moving to the next question okay so this is the leaderboard next question okay get ready so now these are very easy questions you can solve in minute not in minute in seconds hydrochloric acid is used to clean metal the acid react with oxide layer on the surface of metal forming a salt and water which word describes the metal oxide very easy we have discussed this question yes I think this time all of you will answer before times get time get over so let's see how many of you are able to finish this question before time this we have discussed so many times yes okay 59 have answered what you are thinking just think about few minutes back I told you one statement just think about that okay I think you are not getting yet yes yes yes last few minutes two seconds and times up okay so the answer is b very good most of you got the answer good so the question was metallic oxides are basic in nature that's it few minutes back I told you no need to go through the explanation metallic oxides are basic okay I think who is leading okay oh uncle sir came down now arian is leading very good arian give it up moving to the next question now you can see it easily it's a clearly visible which statement is not correct when the base react with ammonium salt ammonia is given off okay I don't know when an acid react with base neutralization takes place maybe when an acid react with carbonate carbon dioxide is given off god knows when the acidity of a solution increases the pH increase I don't know you will only tell me what it what we are going to do in this question oh 55 I've already answered by the time I finish reading which statement is not correct okay you must have read the word not those are not read this may you may lose the marks oh very good aditya okay fine so the answer of this question is D and most of you got the answer of this question okay now what I want to why I gave you this question to convey you one very important reaction you know there is a one option given in the question if you remember there is a one option what is that option that a with an acid reacts with a carbonate carbon dioxide is given off that is a very very important point let's say you have let's say you have HCl okay and you have some carbonate Na2CO3 what will be the product tell me I'm not going to write what you people will going to tell me and I told you in your in class what is going to form here anyone what is the product when HCl and Na2CO3 reacts HCl and Na2CO3 no one very good those who are writing H2CO3 they are completely wrong NaCl plus H2O plus CO2 I told you one fact whenever H2CO3 and whenever H2SO3 forms in product they are very unstable they break quickly and give water and CO2 and H2O and SO2 always remember these two things will never form in the product because they are not stable at all is it clear moving to the next question yes very good most of you got this fine moving to the next one now you will have a very easy question let's see what is the leaderboard now okay Harshita is leading next question which reaction is not a characteristic of acid quickly answer this question which reaction is not a characteristic of an acid it dissolves magnesium oxide think think it produces ammonia from ammonium compounds again think it produces carbon dioxide from carbonate I don't know it produces hydrogen from zinc metal very good question utilizes all the four points which we discuss in today's class all four points and very important question if you are going to get this question right means you have paid attention and whatever I explain is not that tough okay most of you have answered but still 20 more students needs need to answer quickly answer the question okay fine answer of this question is be very good you know magnesium oxide is basic in nature HCl will dissolve it acid base reaction and whenever there is a acid okay it will give you and with carbonate it will give you CO2 ammonia will not liberated with base ammonia will be liberated with base not with acid and zinc plus hydrogen zinc plus HCl give hydrogen displacement reaction because zinc is at the higher on reactivity series is it clear to all of you zinc is in the higher of reactivity series that's why you will get hydrogen gas all four options we have discussed in previous questions okay next very easy question you should not take more than 10 seconds okay fine balancing of a chemical reaction and I hope that all students will go in to do this mission right okay fine last few seconds do it fast okay so answer for this question is what happened Anushka oh didn't balance very good this shows that you're how you oh god why you people did this and it is the NACL reaction you must not have balanced the reaction I think yes you should balance the reaction NACL will form okay I don't think that you need need explanation for this but since most of you have made the mistake I am going to show you the question it is nothing but last option Na2CO3 plus HCl NaCl CO2 plus water it is a balancing part that's it okay next question so easy yes why you made mistake in this see this this question tells like the importance of reading the options don't just take the option without saying it properly okay next question okay this is the big question again so three three chemicals PQR which is dissolved in water the table shows some of the reaction of these solutions reaction with sodium carbonate is added reaction when heated with solid ammonium chloride so PQR are given with P gas evolved no reaction in second option with Q no reaction gas evolved with third no reaction no reaction the pH of the three solution was also measured what are the correct pH value of these solutions easy question it is easy for you now because we have discussed so many questions related to this if anyone is facing any problem please let me know I will read it again still you have 40 seconds question is I read it now the reaction with solid sodium carbonate is added reaction when heated with solid ammonium chloride two option gas evolved no reaction no reaction gas evolved no reaction no reaction a simple question I want to tell you just think in which in if it is acid if it is acid will it give the gas with carbonate if it is a base will it give the gas with carbonate the only thing is you need to think about okay fine okay so most of you have given right answer very good so answer is always remember the few minutes back I told you whenever there is a whenever there is a ammonium salt with ammonia pH ammonia of pH is ammonium salt with alkali give ammonia gas and pH must be greater than 7 and so carbonate salt will give gas with acid that's it that was the question okay moving to the next this is the second last question and then we'll finish it there only yes do it fast this substance is most acidic okay fine most of you have answered which substance is most acidic and answer is answer is answer it fast okay answer is lemon juice I think most of you have done this right so let's see still if you have done mistake no problem next is last question of this class and Aniket is leading good and the last question of this class is this let's finish it fast carbon dioxide is produced when x reacts with ethanol and y reacts with sodium carbonate write the reaction I would recommend you to write the reaction you will get the answer x and y options are given to you write the reaction then only you will able to answer the question y reacts with sodium carbonate sodium carbonate is Na2CO3 Na2CO3 is basic in nature okay x reacts with ethanol reacts with ethanol is a kind of ethanol is a kind of fuel if you have a fuel what will happen okay so I think most of you have answered I have already given you the hint sodium carbonate is a basic okay sodium carbonate is a base won't react with base good so mixed answer sodium carbonate is a base it will react with acid and ethanol is a fuel ethanol is CS3OH CS3CH2OH if you don't know the formula it's fine whenever it is I told you it is a fuel then a fuel react with oxygen it gives you carbon dioxide you know this thing yes or no fuel reacts with oxygen gives you carbon dioxide that's all for today we will see the leaderboard now and the leaderboard says that who is leading answers okay fine sorry for extension of the class and it says Aniket Gupta is leading from INR10 and then Harsita RNR okay good congratulations Aniket very good well done good okay did you learn something in today's class have you learned something new yes okay bye take care we'll meet on next centaur of chemistry bye thank you thank you