 Yes, sir. Hello. Yes, sir. Good morning. We will start the class in five minutes. Good morning, sir. Good morning. How are you? Good, sir. How many of you are there? Only four of you. Where are others? Any idea? No. How is Aditya? The reason Thailand. Any conversation? I don't know when it's coming back only. Okay. Okay, so we'll start today. Polymer. Okay. Small chapter, we can finish it today itself. I have shared one video yesterday on the group. That video is on surface chemistry. Okay, I'll take that class of this chemistry. It's not like I won't take, I take that class. But if you get time, you can go through once. Okay, I'll discuss that when I take the class of surface chemistry. Okay, so just a second. Can you read it? Yes, sir. We'll just delete this board and we'll start. We'll start with polymers. Okay. What is a polymer? Any idea? Anything you can say about this? Association of molecules. Association of molecules. Any example of polymers? Nylon. Like, no, in daily use, anything that we use, which is, which comes under this category. Can it be like an organic polymer also? Anything? Sucrose. What? Sucrose. Okay. Okay. What about the bottle that we use? Water bottle. Is that a kind of polymer? The wire that we use, the cable wire. Okay. The laptop, this buttons that you have, keys or this material of this laptop. Okay. Cable wire that we have. Any kind of wire you see. Switchboard is the kind of polymer. Plastic box that we use in kitchen to keep those, you know, pulses and spices and all. Those plastic box are also a kind of polymers. Okay. Anything, like, polymers is a very vast application in our daily life. Every day we use different different kinds of polymers. Okay. So that's why, you know, the application of this is very used in our daily life. That's why this industry is very big. Polymer industry is very big. Okay. The fiber pipes that we have. The pipe that we use to, for the flow of water, from the water tank to, you know, in the tap and on kitchen everywhere, washroom, wherever we use those pipes. Okay. So all those materials comes under the category of polymer. Okay. Depending upon the strength required for a given purpose, we build the polymer and then we use it. Okay. So that's why, like I said, the industry is very big. And we, on a daily basis, we use these kind of polymers. Okay. So that's why when you do some research, work masters in polymer technology and all, there is a very good scope of, you know, good career opportunity we have. Because like I have given you many examples that comes under polymers and we use daily in our life. Okay. So that's how the thing is, like, so polymers are what? Polymers are made up of two or more different kinds of molecules. Okay. Different or same kinds. Okay. Two or more different or same kind of compounds. These compounds are the basic constituents. Okay. The basic constituents of the polymers and we call it as monomers. Okay. You must have heard about monomer, dimer and all. Right. So dimer comes under the category of polymer because we define what? When two or more substance combines together to give a large complex structure, that compound is known as polymer. Okay. So application of polymers uses we have discussed. Okay. Now we are going to see in this chapter, the chapter is heretical. Okay. You won't get any numerical question to this. The point is, you need to know for a given compounds, what is the monomer of that? Okay. What kind of linkage is there? What is the repeating unit in the polymer? Okay. Those things you have to keep in mind. Okay. And since it is doing this in chemistry, we also have to see the reactions which involves in the formation of polymers. Okay. But like I said, reactions, hardly they ask in this, they will ask you the monomers of different polymers, the repeating unit. Okay. And what kind of linkage is there? There's all those things we'll discuss one by one. First of all, you'll write down the definition of polymers. Definition you write down. Write down polymers are polymers are a very large complex molecules. Polymers are very large complex molecules, which has, which has very high molecular masses, very high molecular masses, masses, and each molecule consists of, each molecule consists of, each molecule means polymer molecules. Each molecule consists of a very large number of simple, a very large number of, large number of simple structural units, structural units joined together, structural units joined together through covalent bond, through covalent bond. These structural units, next line, write down, these structural units that you have, each of these structural units are called monomers. They're called monomers. Next line, the method or process by which, process by which monomers, monomers converts into, monomers converts into polymers are called polymerization technique, are called polymerization technique. And this phenomenon is polymerization. So this is the definition of polymer, okay? But definition, obviously they won't ask. Examples of polymers, I have given you many examples, write down. The examples are, we have polyethylene, polyethylene is nothing but polythene that we use, the plastic bag, T-T-H-E-N polythene, okay? We can have polyvinyl chloride PVC, we can have nylon 66, etc. There are many other things, okay? Plastic bag, plastic box, okay? Cable, okay? The electric board, which is, all these are examples of polymers, okay? Which are there in day-to-day life that we use, okay? Now what I said, polymers are made up of, made up of what? Two or more monomers, basic structural unit, which we call it as monomer. Two or more basic structural unit known as monomers, okay? So these polymers can take same type of monomer also, a different type of monomer also, okay? So polymers, again we can classify this polymer into two types, okay? Based upon, based upon, based on the structural unit present, and structural unit means what? The monomers, okay? Based upon the structural unit present. Two types of polymers we have based on the structural unit. The first type, we call it as homopolymers, homopolymers. And the second one is copolymers. In homopolymers, the repeating structural unit, you have to memorize this, you have to keep this in mind, the repeating structural unit are derived from only one type, only one type of monomer units. Only one type of monomer units, okay? Same monomer will have in this, okay? We cannot have different monomers. Like, you see polyethylene, I have written here one example, okay? The monomer of polyethylene is ethylene. And that's why the polymer of ethylene is polyethylene. Got it? Polymer of propylene is polypropylene. Okay, like that we write down the name. So with this polyethylene word, if somebody asks you, what is the monomer here? Remove this poly, you'll get the name of the monomer that is ethylene. Okay? So polyethylene is a type of homopolymers. That's what you have to memorize, okay? They may ask you this question. They'll give you four options and they say, which one of these is homopolymer or copolymer, okay? So you should know the definition of it. What is homopolymer? What is copolymer? Then only you can say whether the repeating structural unit, which is nothing but monomers, okay? We have, either we have same type of monomers or different types of monomers, okay? We are not concerned with the number of monomers present, but we have to see like whether we have same kind of monomer like in polyethylene or different kind of monomer. I'll give you the example of that also, okay? Homopolymers are those polymers where the repeating structural unit are same, only one type of repeating structural unit. Copolymer, it is reverse of it. In copolymers, what happens? We have different repeating structural unit, okay? With the two monomers that we use here or simply in the one line we'll write down, for copolymers, we use different types of monomers of structural unit, which is monomers. The example of copolymer is nylon 66. We'll do one by one the different polymers we have and then there also we'll see this one is homopolymer, this one is copolymer. Just you copy it down first? Copy it, sir. Done, sir. Done? Okay. See, this is one type of classification we have which is based on the structural unit present, okay? Classification of polymer is also there on the basis of source. Write down the next one. Classification based on, I'll just write down the second one here. The heading is classification based on source. Based on source, we have two types of polymers. One is natural polymers, which exists naturally. That's the name suggests. Write down just one line. Polymers, which are found in nature, like animal plants are natural polymers. Okay, like starch. Example I'll write down here. Natural polymers, the examples are starch, cellulose, protein, proteins, nucleic acid, nucleic acid, etc. Nucleic acid we haven't done in biomolecules. No, sir. That part was left out. Okay, I'll do that. Nucleic acid, it takes half an hour. Okay, we'll finish that. It's not that important for, you know, a chemistry point of view, but we'll go through once. Okay, we'll do that. Okay, these are natural polymers. Second one is synthetic. Synthetic means what? Manmade. Any example of synthetic polymers? Nylon. Yes, nylon, polythene, polystyrene, PVC, beccalite, dechron, write down all these examples. Nylon, polyethylene, polystyrene, PVC, polyvinyl chloride, beccalite, dechron, DAC, RON. Now, another type of classification we have, which is based on structure. I'm not giving you this as you listen to me. Based on structure, we have linear polymers, branched chain polymers, and three-dimensional network polymers. Okay? In three-dimensional polymers, there are cross-link. I'll just draw the structure here. You see, the first one we have, like, here I am not giving you. Just you draw the structure, because these are not important. Based on source, classification based on source, you write down. See, one thing I'll tell you here is that for these chapters, okay, like, we have polymers, biomolecules, to a certain extent, biomolecules to a certain extent, then surface chemistry, chemistry in everyday life. For these chapters, NCRT is more than enough. You don't have to read any other book, okay, from beginning to end. The focus should be on NCRT. They prepare questions directly from NCRT. They pick one or two lines, and they prepare questions from that, okay? So my suggestion is, I'll cover everything here in the class, but when you want to go through on your own, just read NCRT. For questions, you can refer the assignments on any other book, okay? But for theory part, don't go to any other book that you have. NCRT is more than enough for theory, okay? So theory part will focus on whatever, you know, theory given in NCRT, not more than that, okay? Based on structure, we have three types of polymers. The first one is linear polymers. The name suggests, what will happen in linear polymers will have a linear structure. There won't be any branch, okay? It should be based on structure. Based on structure, yes. It is source I have written by mistake. Make it structure. It means you're not sleepy. Yes, Parvus? Sir, I woke up. What? Based on structure. Okay, so like I said here, there's linear polymer, there's no branch in here. It's a linear polymer like this. So it's just one layer, so you can have another layer like this one. So it is a linear polymer. It looks good. Second one we have branched chain polymer. Like the name suggests, in this we have branches also. For example, you see, this is the polymer we have, suppose, and in this we have branches present like this. This is branched chain polymers. Third one is we have three-dimensional sheet structure. Three-dimensional network polymers also we call it as. Three-dimensional network polymers. Three-dimensional network polymers. In this we have cross-linking. Write down. In this we have cross-linking. Cross-linking means what? Suppose this is the layer one, another layer, we have another layer like this. All these layers like here, these are linked together by some bonds. Okay, this is cross-linking. See this one is cross-linking. Like this, the cross-linking were present. Okay, so write down. This is the cross-linking we have. So because of this cross-linking, there is strength increases a bit. Okay. So these kind of polymers are rigid, hard, rigid and brittle. So can you give an example for the 3D thing? Okay, I will give you. Write down. These are hard, rigid and brittle. The example of this is beccalite. Urea formaldehyde polymer. Write down. Urea formaldehyde polymer beccalite. Melamine formaldehyde polymer. I will give you examples for all 3. Because examples are important here. For this it is polythene, nylons, polystyles. Nylons, polystyles. For this one, we have glycogen, amylopectin. Amylopectin is there in amino acids. We will discuss that. To one type of amino acid we have this. And this is beccalite, urea formaldehyde and melamine formaldehyde polymers. So what kind of starch? Sorry? Starch comes under which category, sir? Starch comes under the third one. Because amylose and amylopectin? Yes. Because all these starch proteins, cellulose, they have very complex structure. Very large, huge complex structure we have. In all these we have cross-linked. Last class we were discussing proteins, how they form, there will be cyclic helical structure because of hydrogen bonding and all. There are cross-linking present in all these kind of molecules. Starch, cellulose, proteins and all. All these comes under three-dimensional network. Okay? Yes, sir. Okay. Now there are few examples we will discuss. Like I said other, classification also we have. Classification based on synthesis. How the polymers forms. Two types of reaction generally we have. Addition and condensation. Right? So that we call it as addition polymerization and condensation polymerization. Addition polymerization, two molecules joins together. Okay? In condensation, like molecules like H2O and H3 goes out and they joins together. Okay? So that we will discuss in reactions involved in polymerization. So that is also one kind of classification. And we say this as what? Based on synthesis. What reaction we are using for the synthesis of one kind of polymers. So that is also comes under classification. But we will do that in reactions involved in polymerization. Okay? So before going into that, there are few examples that we should know. The examples. The first one is H2C double bond TH2. What is the name of this molecule? Ethene. Ethylene. Okay, both we can see. So when it goes under polymerization, it gives you what? It gives you polyethylene. Polyethylene or polythene also you can see. Which we use in plastic bags. So this is ethylene. And on polymerization it gives polyethylene. Okay? What is the structure of this polyethylene? It is like this. We have CH2. CH2. CH2, CH2. CH2, CH2. And so on. In short, we can also write this as open bond CH2. CH2. Open bond. Bracket N. This is actually a representative. There are N such molecules present in this. And that's why this is polymer. And the name of this is polyethylene. Am I clear? For polymerization what happens? We should have a definite pressure, temperature or catalyst. So whatever is required will provide you for this reaction. And then the reaction takes place. Okay? So the method by which this monomer ethylene, this monomer converts into polymer. Those methods are polymerization technique. And this phenomenon is polymerization. Okay? What is the use of polyethylene? Use in the formation of plastic bag. You know that? Yes, sir. If you're using plastic bag, if you're carrying some goods in the plastic bag, then they can ask you for 2000 rupees. You know that the soft shell, soft molecule 5000, and the person who is taking goods into the plastic bag, they have to pay 2000 rupees. Okay? So don't use plastic bag. So this is one uses of polyethylene. Now the reference molecule is this. On the basis of this only, we'll give you another molecule, which is this. Now if you remove one hydrogen here, with chlorine, T H 2, double bond C H, and here we have C L. When you do the polymerization of it, what you'll get? First of all, you tell me the name of this compound. The name of this compound is what? Chloroethylene. A? Okay. Vinyl chloride. Yes. At vinyl position, we have chlorine present. This molecule is vinyl chloride. And the polymerization of this gives you polyvinyl chloride. Ethylene gives polyethylene. Vinyl chloride gives polyvinyl chloride. Got it? The structure is what? If you draw the structure, T H 2, C H, C L, connected with the other molecule, C H 2, C H, C L, C H 2, C H, C L, and so on. In short, if I write this as T H 2, T H, C L, and N times. Okay. The example of this PVC, sorry, PVC, the use of this in making pipes. Pipes, but I may use crypto. Okay. One more thing I forgot to tell you here, what is the repeating unit? What is the repeating unit here? See, this N times means what? This is the repeating unit we have. So like this, you have to, you should know the repeating unit of the molecules. Like this one is easy, so you don't have to worry about it. They won't ask these questions also. But for others, we'll see what are the repeating units. There it is important. One kind of one, this kind of question they ask. Similarly, the repeating unit is this one here. Is there a name for these repeating units? It's vinyl chloride only for this one. Name they won't ask. They'll draw the structure. Now, if I ask you, these two are homopolymers or copolymers? Homo polymers. Yes, because the monomer is same. We have only one type of monomer. That's why these are homopolymers, not copolymers. Like this, you have to keep in mind that whatever examples you are looking at, you should focus on the repeating unit, what kind of polymers it is, homopolymer, copolymer, and then what are the monomers? If it is homopolymer, fine, only one monomer will be there. If it is copolymer, then what are the two monomers we use for the production of this, and what are the uses? These two things you must focus on. Third type, if I remove this chlorine and add phenyl group, like this one, CH2 double bond CH, and here we have the benzene ring. So polymerization of this gives, the name of this compound is styrene, and the polymerization of this gives what? polystyrene. The use of this is, I am not drawing the structure here again, but can you tell me what is the repeating unit of this? CH2 single bond CH. CH2 single bond CH, phenyl ring, and open bond both sides, and like that you can draw the structure. I am not drawing it here again, because we know how to draw this. Another example you see, we remove this benzene ring and we attach CN here, cyanide. This molecule, we call it as acrylonitrile, A-C-R-Y-O nitrile. And on polymerization, this gives what? polyacrylonitrile. All these are homopolymers. This, we also call it as Orlon, the name of polyacrylonitrile, the general name is Orlon, O-R-L-O-N. Polyacrylonitrile we use for the formation of fibres, uses it. Fifth one, if I remove all the hydrogen atom and add fluorine, TF2 double bond CF2, polymerization. This compound is tetrafluoro, tetrafluoro ethylene. It's the monomer. And polymerization of this gives you the compound, which we call it as teflon. And the teflon that use of this is the formation of non-pupil. Even mouse feet is made of teflon. Yes. Yes, sir. So these four or five examples you must remember, all these are examples of homopolymers, not copolymers. Okay. Now the next thing is what are the polymerization technique we have? That is reaction. What reactions involve in polymerization? Write down the reaction involved in vulcanization. Okay. So two types of polymerization reaction we have. So heading is polymerization reaction. Like I said, two types of polymerization reaction we have. The first one is addition polymerization. Addition polymerization. Leave some space here. Second one you write down condensation polymerization. Condensation polymerization. Addition polymerization also we have three types in it. The first one is free radical polymerization. The second one is cationic polymerization. Polymerization. And the third one is anionic polymerization. Condensation polymerization, what happens into this? The molecules like water, NH3, HDL, etc. goes out. Eliminates. Okay. And the two molecules combined. Okay. So these are the two types of reaction we have. First of all we will see free radical polymerization. So next heading you write down free radical. Cationic and anionic we will not go into that detail. I will just give you the idea how it forms. Basically the difference in these three reactions is what? Intermediate or free radical, cation and anion. That is the only difference. Okay. So reaction part is not that important. But free radical we will see that. Write down the first one. Free radical polymerization. Free radical polymerization. Free radical polymerization. This mechanism is, this mechanism involves the formation of free radical. Okay. And that's why this, we also call it as chain growth polymerization. Because in free radical mechanism we know the initiation step, then chain propagation, then chain termination. So this we also call it as chain growth polymerization. Growth polymerization. And since free radical involves in this, so these kind of reaction is very difficult to stop. Difficult to stop. Difficult to stop means we do not have any control on this reaction. Any control on this reaction. Okay. So that's why we most probably will get a very complex structure into it. If you try to control it, it's not possible because the intermediate is free radical, which is highly reactive. And we know in free radical reactions, we do not have any control into that. Okay. That is one thing. Now for this reaction, since it involves free radical, so this reaction actually requires a free radical agent. Which forms free radical generally. So for this reaction, we need a free radical agent. Free radical agent are those molecules or compounds which helps in the formation of free radical. Okay. It helps in the formation of free radical. Like for example, we can take any peroxide or oxygen. O2 as a catalyst we can take or we can take any peroxide for this purpose. In general, we use benzoil peroxide as free radical agent. So benzoil peroxide, if you look at the structure, the structure of benzoil peroxide is this pH C double bond O and then we have a peroxide linkage C double bond O and pH. Okay. So what happens with this benzoil peroxide? All these peroxy compounds where we have this linkage, peroxy linkage, are generally not that stable. And when you heat this slightly, this bond dissociates and it forms radical, which is pH C double bond O, O radical plus pH C double bond O, O radical. Why this happens? Because these two oxygen, okay, has lone pair of electron on it and that's why we have very high lone pair, lone pair repulsion and hence the dissociation of this bond is easier. So one of the electron here is taken up by this oxygen and another one is taken up by this oxygen and it forms a free radical like this. We also know that this free radical has property to eliminate neutral molecule, neutral molecule and forms new free radical. So in this what happens, two CO2 molecule eliminates, I'm writing down for both one, one CO2 from this, one CO2 from this, eliminate and we'll get two phenyl radical. I should write down this. We'll get two phenyl radical. Got it? Yes sir. So this is the first step of the reaction and this is step like I said, we call it as chain initiation step, theoretical mechanism, chain initiation step. Okay, next step is what? Chain propagation. So in chain propagation what happens, this phenyl radical, in the next step, this phenyl radical has a free radical here. It reacts with the ethylene that you have and with a suitable pressure temperature catalyst. So here this one electron comes over here one electron comes over here and these two joints like this. So the product is this, CH single bond CH2 radical. Like this only, the chain propagates. We have another molecule also, CH2 double bond CH2 combines with this here and we'll get a long chain. So in short, if I write down n times if this steps goes, then it gives pH CH2 CH2 CH2 CH2 radical. This is suppose n times. Like this compound will get CH2 radical. Okay, and finally what happens, this one and this one club together because we have this kind of many compounds are there. So all these clubs together and it forms pH CH2 CH2 CH the whole thing. Suppose this is X number of times. Like this only, okay. And finally this pH pH goes out and we'll get a long chain compound here. So basically this reaction involves this last step is chain termination when all the free radical combines together this step is chain termination. From here to here it is chain propagation and till here it is chain initiation. Okay, so like you see theoretical involves in this reaction the structure of the polymer that you get here is very complex. It is there is no proper arrangement order arrangement here. Why? Because the intermediate is theoretical which is highly reactive and we do not have any control in such reaction. Copy it down. The heating unit is just CH2 CH2 right? Yes, yes, yes. Monomer is that only you know CH2 double bottom CH2 so with that only we'll get the repeating unit. For homopolymers the repeating unit is not that important. For copolymer it is important. We'll see that also. Can we go to the next page? Okay. So similarly we have cationic polymerization. There the intermediate is in cation. Okay. Anionic polymerization intermediate is in anion. Okay. So that mechanism like I said even this is also not important. The only thing is if you have any cation suppose H plus present then this CH2 double bond CH2 will attack like this if I write down here you see CH2 double bond CH2 we have with H plus it forms CH3, CH2 plus. Now this reacts with again CH2 double bond CH2 and the reaction proceeds. Okay. So that's how the reaction goes in cationic polymerization and anionic may will have this if you have suppose a salt like K NH2 so it is K plus NH2 minus and when this reacts with CH2 double bond CH2 so in this what happens this minus attacks on to this carbon and this goes here. So we'll get CH2 NH2 NH2 CH2 and CH2 negative. So this is cationic polymerization. This is anionic polymerization. Again this negative charge will attack on to this molecule shift and we get a long chain compound. That's how it goes. So like I said it is not important. Okay. The mechanism here. Okay. This is the three reaction we have addition and addition polymerization which involves free radical cationic polymerization and anionic polymerization. The another one we have here is condensation polymerization. Okay. So in condensation polymerization what happens like I said the neutral molecules like H2O NH3 goes out. So the second reaction we have look at this reaction. This molecule reacts with glycol which is HO CH2 CH2 over which. So what happens in this when you heat this H2O molecules goes out H2O molecules goes out and these two combine to minus H2O and the product will be HO C-double bond O a benzene ring C-double bond O O CH2 CH2 O H. Okay. This molecule the name of this molecule is terfithalic acid and this one is glycol the polymer that you get here we call it as pteriline polyester or daikon. I'll write down the name but first of all you see here these two combines and in the next step since we have two different monomers here so which one we can use in the next step to get the large complex structure polymer structure which of these two monomers we should use in the next step. Tell me if we want complexity in terfithalic Which one? Acid thing Actually you see this end is an acid right this end is an acid and this is an alcohol so actually we can use any one of these monomers in the next step the only thing is if you use alcohol here the reaction takes place to the acid end the acid here then the reaction takes place to the alcohol end got it? now you see suppose I am taking this acid in the next step which is in short I'll write down pH COOH and COOH then the reaction takes place here right alcohol end from here to this CH2 the thing will be same the structure is H O C double bond O C double bond O O CH2 CH2 and then again H2O goes out so this connect with an oxygen C double bond O then benzene ring C double bond O OH take a C double bond O OH now you see here in the next step now we are bound to use what we are bound to use only the alcohol because both end we have what we have acid so basically we will go alternate in this way first we can use in the first step we get this and then we can use any one of these monomers alcohol or acid but if you use alcohol here next will be acid acid here next will be alcohol like that we will go alternate okay now the thing is if this reaction takes place I will write down one more step here the product is this we get after this reaction the product is this we have H O C double bond O C double bond O O CH2 CH2 O C double bond O and then we have a ring C double bond O O CH2 CH2 OH this is the product we get after this reaction now you tell me here what is the repeating unit for this monomer give me a minute I am coming tell me that find out the repeating unit yes tell me the repeating unit so is it O C double bond O phenyl C double bond O OH CH2 CH2 O I think it is only till CH2 CH2 till CH2 CH2 oh yeah that comes from the other thing just a second so the repeating unit here is from this C double bond O will take this here this C double bond O to this oxygen one change I have this is this side also the change we have which is OH here and this will take this hydrogen this hydrogen so repeating unit is this so this you should know for a given polymer and what kind of the name of this polymer is we call it as pteriline which we also known as this as polyester because you see C O O R group we have so it is polyester ok and the common name is Dachron also R O N so all these names are important so basically Dachron or polyester or pteriline is a copolymer or homopolymer copolymer it is a copolymer because two different monomer they use it that's what you need to keep in mind there are difference in this condensation and addition polymerization is what that this reaction we can stop at any step you won't hit it reaction won't go in the next step ok so this can be stopped the reaction is under control that's what we can the reaction is under control unlike the addition polymerization where we have no control on the reaction so that's the difference we have here some more example we will see can you tell me the formula of adipic acid yes don't know sir don't know I have given you this in carboxylic acid chapter could you repeat which acid adipic acid just a second adipic acid don't know do you remember this CH2 CH2 COOH COOH here we have COOH and this is N times so if N is 0 what is the name of the molecule because it is COOH COOH COOH because there is no CH2 present in between when N is 0 when N is 1 malonic acid when N is 2 succinic acid when N is 3 glutaric acid when N is 4 it is adipic acid and when N is 5 it is pymalic acid ok so I have given you this how do you memorize this 0 to 5 N OMSGAP you remember this ohmscap yes so this you must remember it helps you in getting the formula of the molecule so adipic acid and hexamethylene diamine so adipic acid the formula is HOOC CH2 N value for adipic acid 4 so this is 4 COOH and this combines with hexamethylene diamine ok so hexamethylene diamine is this CH2, NH2 here also we have NH2 hexamethylene so CH2 6 got it so second one is hexamethylene diamine ok when condensation takes place between the two H2O molecules goes out and it forms the product here is HOC double bond O CH2 4 C double bond O O combines with NH should we have O here sorry C double bond O OH and H forms H2O and it gives NH CH2 6 NH2 is the compound we get the repeating unit if you see it is from this C double bond O to write down this way the repeating unit will be from here to this N times of this to the polymers ok so this molecule this polymer in general we call it as polyamide why polyamide because in this we have amide linkage CO NH bond so it is an amide linkage so in the polymer like this we have many amide linkage that's why we call it as polyamide ok and this commercial name of polyamide we also call it as nylon what 6 6 sir does condensation polymerization happen only for copolymers not necessary it is possible with homo polymers also if you have suppose two molecules of adipic acid then also it's possible ok but yes in that case you will get a molecule which has a bond of C double bond O O C double bond O ok so that is an ester kind of molecule you will get but it is possible with homo polymers also in homo polymers also like two carboxylic acid may combines what a molecules goes out so it is possible over there also condition will be different it may stop after dimer itself because dimer is also a polymer and why would it stop suppose one end we have this end we have COOH open then we can take another same molecule this end will react as open suppose we have COOH and COOH these two react we will get a dimer this end and this end is open so now this end will react like this it goes if condition is not there then it stops won't there be any repulsion because it's the same type if you compare yes there will be but the question whether it is possible or not it's possible yes yes that's it Nylon 6 6 is a commercial name for this this 6 and 6 stands for the number of carbon atom in the 2 monomer here you see the number of carbon atom is 6 4 5 and 6 so this 6 and 6 represents right down here the number of carbon atom present in the monomer polyamides nylon 66 is a polyamide it has amide linkage hence it is polyamide CO NH next we have to discuss about the one last classification of polymers that is based on right down classification based on molecular forces based on molecular forces based on molecular forces so depending upon the strength of the force that is involved in the polymers this classification is done and it is important the first one is lastomers the first one is elastomers right down into this in short you write down these are the polymers in which the intermolecular force of attraction is very weak elastomers in short you write down point wise IMF IMF intermolecular force so IMF is weakest here and when IMF is weakest so obviously the polymers can slide over the layer we have layer by layer structure so when intermolecular force is weak then all these layer can slide onto each other that's why they have elasticity property they have high degree of elasticity high degree of elasticity and what we said they have ability to stretch over their normal length actually 10 times of their normal length they can stretch but that is not important okay the structure is irregular write down irregular shape irregular shape we have and few cross links are there and few cross links okay example you write down examples of elastomers elastomers are natural rubber natural rubber examples Buna S you know what is Buna S no sir you do not know okay Buna S is a copolymer we will discuss that Buna S is a copolymer we will we will discuss that rubber when we do rubber we will discuss into that we will just write down the example now okay Buna S so vulcanized rubber also here we take as this thing elastomers vulcanized rubber is important they have asked this question many times in the exam vulcanized rubber so in this only we will discuss what is vulcanized rubber so write down the heading write down write down the vulcanization is a process excuse me vulcanization is a process by which the tensile strength elasticity the tensile strength elasticity and resistance of natural rubber can be increased can be increased okay next line in this process in this process the rubber is heating with sulphur heating with sulphur and in bracket you write down of the sulphur we use 3 to 5% of sulphur means the rubber is heating with 3 to 5% of sulphur during vulcanization the sulphur bridges the sulphur bridges or the cross links sulphur bridges sulphur bridges or the cross links or the cross links forms between the polymer chain and this is known as vulcanized rubber this is known as vulcanized rubber so basically the natural rubber you have suppose suppose the rubber natural rubber is this we have different you know chain in this we have natural rubber is this suppose this is natural rubber and when you heat this with 3 to 5% sulphur then there will be a cross link of sulphur bridge between the polymer chain like this suppose the chain we have so all these will have sulphur bridges present between this and that is how the strength increases like this the chain forms ok so this rubber we call it as vulcanized rubber this is natural rubber so this vulcanized rubber they have asked many times in the exam competitive exam also they have asked in board exam also they have asked ok so but there is only one thing you need to keep in mind that the natural rubber is heated with 3 to 5% sulphur to give the rubber which has more tensile strength resistance and all that rubber we call it as vulcanized rubber generally the question that they ask in competitive exam in vulcanization the rubber is heated with what we have 4 options sulphur is the answer ok so that is one type of first classification of molecular based on molecular forces we have of polymers ok second one is fibre is fibre can we take a break now we will take after fibre huh you finish fibre then we will take ok so now fibre we write down the class is still till 1 no I will take my breakfast that is why I am asking anyways we will finish ok no it should be 2 minutes we will finish this fibre so after this fibre we will take a break ok write down um fibre write down in this the intermolecular here you see intermolecular forces weakest here and here the intermolecular force in fibre is the strongest ok IMF strongest here write down the forces involved in this next line the forces involved we write down hydrogen bonding or dipole-dipole interaction dipole-dipole interaction like in case of polyamides nylons are polyamides that also you must remember nylons are polyamides amide linkage is there so in case of polyamides the intermolecular force are due to hydrogen bonding you must remember this polyamide may we have hydrogen bonding but when you have polysters like terylene dichrone that you have polysters we have we have dipole-dipole interaction in polyster and polyacrylonitrile that is orlone see polyster is see polyster is dichrone and polyacrylonitrile is orlone and both we have dipole-dipole interaction this you must remember for both the things dipole-dipole interaction in all these comes under the category of fibres ok they are very strong in terms of their strength ok so when intermolecular forces are strong they have obviously high tensile strength the property strength ok and less elasticity slippery tendency is not there hence less elasticity and the last thing you write down they have high melting point high melting point and low solubility examples must important fibres the examples are dichrone orlone and polyamides ok fine so we will take a break now we will start in 15 minutes what is the time now 10.41 we will start 10.55 ok take a break yes sir ok so fibres we have done next you write down thermoplastic the third type thermoplastic write down the polymers in which the polymers in which the intermolecular force the polymers in which the intermolecular force of attraction are in between elastomers and fibres the intermolecular force of attraction are in between elastomers and fibres so moderate we have here these are linear polymers these are linear polymers hard at room temperature these are linear polymers hard at room temperature and become soft and viscous on heating become soft and viscous on heating and again become rigid on cooling they become soft and viscous on heating and again become rigid in cooling ok example you write down example you write down polythene polypropylene polystyrene PVC teflon polyacrylonitrile there is a term that we use here is plasticisers ok write down that term in this only plasticisers definition of plasticisers you write down those plastics those plastics which do not soft which do not get soft very much on heating can be made soft and workable by addition of certain organic compound called plasticisers those plastics which do not get soft very much on heating can be made soft and workable by the addition of certain organic compounds called plasticisers plasticisers called plasticisers ok there are some examples of plasticisers you must remember dialkyl dialkyl phthalates dialkyl ph-t-h-a-l-a-t-e-s is the one kind of plasticisers ok examples you must remember for next I will write down PVC PVC is extremely stiff PVC polyvinyl chloride is extremely stiff and hard extremely stiff and hard but the addition of di n-butyl phthalate this one di n-butyl ph-t-h-a l-a-t-e this is the general name this is one specific example we are taking PVC is extremely stiff and hard but the addition of di l-butyl phthalate in short in bracket you write down we also call it as D-B-P di n-butyl phthalate makes it soft and rubber like makes it soft and rubber like ok di-octyl phthalate is the another example di-octyl ph-t-h-a-l-a-t-e in short we write it D-O-P is the another example of this plasticisers ok structure of this you see thalic acid is this benzene ring and we have COOH here but that H you remove by butyl group C4H9 it becomes D-B-P C4H9 ok octyl is what C8H17 you need to put here so this is the structure of octyl COO C8H17 COO C8H17 this is D-O-P and this is D-B-P this reply size you must remember ok so this is one thing Cracylphosphate also we use as a plasticisers another example the last one you write down Cracylphosphate the structure is this ME and here we have O-P-B-O-H double bond O this is odd double bond O this is orthocracylphosphate another plasticisers ok so these three examples you must remember done yes sir last one you write down is thermosetting polymers the fourth type thermosetting polymers write down these are semi fluid substance these are semi fluid substance with low molecular weight which when heated which when heated undergo a change in chemical composition ok semi fluid substance with low molecular weight which when heated undergo a change in chemical composition to give a hard and insoluble mass hard and insoluble mass insoluble mass the hardness is because of extensive cross-linking is because of extensive cross-linking ok so cross-linking is again that is the same thing we have a bond between the two layer ok so when you heat this chemical change takes place and cross-linking occurs and hence it becomes hard ok so these are the four different these are the four different types of polymers we have and this classification is based upon the forces involved in it ok right next you see heading you write down rubber classification this is done next is rubber ok there are two types of rubber we have one is natural other one is synthetic ok so natural rubber write down two types of rubber we have natural and synthetic rubber natural and synthetic rubber natural rubber are those which are available in nature available in nature ok available in nature and it is obtained from rubber tree rubber tree and from this we will get material we call it as latex material you must have heard about it latex material and from this we obtain rubber ok so it is available in nature basically ok synthetic rubbers are what these are man made synthetic rubbers are man made the example of natural rubber is natural rubber the one example we have is polyisoprene polyisoprene ok polyisoprene what is the monomer of this can you tell me isoprene isoprene structure of isoprene is what CH2 double bond C single bond CH3 CH double bond CH2 this is isoprene and when this goes under polymerization it forms polyisoprene polyisoprene the structure is this CH2 C double bond CH CH3 CH2 and the open end and this actually you can understand by free radical mechanism this bond pair comes over here this goes here this comes over here this goes here this and this forms a double bond here and this is the open end we have this thing so this is the repeating unit now can you tell me do this molecule does this molecule show GI geometrical isomerism yes or no the groups are all different no what is the you know condition for the double bond to show geometrical isomerism there is a condition okay and what is that condition if you have C double bond C and both the carbon has two different group attached means the group attached at each carbon atom must be different then across this double bond we have two isomer possible cis and trans okay this is the condition of double bond to show GI we can have AB, CD also but we cannot have AA here that is not possible this two must be different this two must be different that is what we have here you see this is CS3 and obviously this is a different group CS3 and this carbon has one hydrogen and one different group so across this double bond we can say that there is GI possible geometrical isomerism possible so it has two form here one is cis other one is trans the cis form of this is soft in nature this cis form of this molecule only we use in rubber this is only used in and we call it as heavy rubber heavy rubber trans is hard in nature this we do not use in rubber and we call it as gattaparcha GU double TA must remember this name GU double TA PERCHA polyisoprene cis form polyisomerism polyisoprene cis form of this is natural synthetic rubber man made rubber there are many examples the second one you write down synthetic rubber man made ok so the first example of this is butadiene rubber butadiene rubber butadiene is the monomer and its structure is what CH2 double bond CH single bond CH double bond CH2 and when you do the polymerization of it you will get CH2 CH double bond CH this is the polymer of this ok and this we call it as poly butadiene poly butadiene ok now another example of this is neoprene neoprene and the monomer of this neoprene is chloroprene the structure is CH double bond CCL CH double bond CH2 the name of this compound is chloroprene ok and when you do the polymerization of it you will get again the similar way CH2 CH double bond CHCH2 we have chlorine here and this is the name of this one is since it is chloroprene so this one is polychloroprene poly chloroprene which we also call it as neoprene ok then can you go to the next page third example third one we have is styrene butadiene rubber styrene butadiene rubber can you tell me the monomer of this yeah what happened monomer is what monomer is styrene and butadiene styrene butadiene rubber we also write it as SBR in short monomers are what one of the monomer is styrene and we know the structure of styrene we have done already CH2 double bond CH and here we have a benzene ring this is styrene and this combines with butadiene butadiene is this CH2 double bond CH single bond CH double bond CH2 ok this we take around 25% in the mixture and this will be 75% in the mixture ok and then it forms under polymerization it forms CH2 CH CH2 CH double bond CH single bond CH2 this is the molecule we get we also call it as actually when you heat this we use sodium as a catalyst here any catalyst in this process and that is why this molecule is also known as duna S duna S this BU stands for butadiene S stands for styrene and N is the catalyst that is sodium that's why we call it as duna S so the monomer of duna S is what is styrene and butadiene catalyst is sodium ok structure is this the fourth one we have acrylonitrile and butadiene rubber so what is the monomer of this acrylonitrile and butadiene the structure of acrylonitrile is what? CH2 double bond CH and here we have CN plus butadiene is CH2 double bond CH single bond CH double bond CH2 heat this in presence of sodium catalyst the structure is CH2 CH CN CH2 CH double bond CH single bond CH2 that is what we get and we also call it as BUNA butadiene sodium nitrile acrylonitrile next write down we use a catalyst to get the ordered structure of any polymer and that catalyst we call it as Ziegler NETTA catalyst ok what is this Ziegler NETTA catalyst first of all the formula you should remember ok it is titanium chloride the mixture of TICL4 with trialkyl aluminium AlR3 trialkyl aluminium our group is the alkyl group generally we take ethyl but it can be anything actually ok so if I draw a polymeric structure of polypropylene so propylene the structure is this CH2 double bond CH CH3 this is propylene and the polymerization of this gives this structure CH2 CH3 CH3 CH2 CH3 CH this side we have ok like this it goes do we have any carol carbon in this molecule this is polypropylene do we have any carol carbon in this no no I think we have the first one how many at least in these this is structure where two molecules have joined how many carol carbon we have I think except for that middle CH2 the carol but then aren't the same groups repeated so after in the left side CH2 is attached to after this CH2 again we have CCS3H see this carbon then won't it be won't it be same on both the sides yeah this side also we have CH2 and then the same thing this this carbon is not a carol carbon because there is two hydrogen on it take care what about this carbon we have one molecule this hydrogen one molecule is this and another molecule is this symmetrical arrangement we are not considering got it we are considering what we are considering if the number of carbon on this side and this side is different then this carbon is the carol carbon we have or for this molecule you see when we have dimer this then this carbon for at least this one is carol carbon because this group is this and this we have this side similarly this carbon is also a carol carbon yes no all the alternate carbon which has four different group attached with it are the carol carbon so now when it is carol carbon these three and H which is attached to this carol carbon their arrangement can be anything okay so that arrangement we are trying to understand here so what is the arrangement we have here you see one possible arrangement is this okay one possibility is what all CS3 present on the same side like this and one arrangement what one CS3 coming out of the plane other one is going into the plane then out of the plane into the plane alternate and here we do not have any fixed arrangement it is randomly arranged like this there is no fixed arrangement here okay because we do not have any control in such reaction like I discussed about this radical mechanism we have we do not have control on these reactions so we can get any one of these possibilities okay whether the one possible arrangement is what all CS3 on the same side then alternate and then random arrangement overall point I am trying to make is what that the possibility is to get either ordered arrangement or disordered arrangement both possibility are there so when all the CS3 group present on the same side okay this arrangement we call it as isotactic arrangement isotactic arrangement when all CS3 on the same side when it is alternate like this it is syndiotactic syndiotactic and when there is no arrangement random arrangement if it is there it is random arrangement so this random arrangement we call it as atactic so these two are actually regular arrangement right whether it is isotactic or syndiotactic the arrangement there is a pattern regular arrangement we have okay so this regular arrangement arrangement they have good physical properties because ordered arrangement we have so their physical property is better good and useful also since the physical property is good high density we have so this one is useful also both isotactic and syndiotactic both are useful they have good physical properties because they have ordered arrangement arrangement will have a fixed pattern here this one also and this one also but random arrangement their physical property is not good not not good physical properties that is why we will try to and this is not useful also since the physical property is not good that is why we try to avoid this particular arrangement atactic arrangement okay and to avoid this arrangement we use a catalyst and that catalyst we call it as jigler netta catalyst got it so this point you write down the structure of the structure of polymers depends upon the type of mechanism the structure of the polymer depends upon the type of mechanism next line in free radical mechanism in free radical mechanism there is no control over the reaction and the possibility to get and the possibility to get the random arrangement of molecules is high the possibility to get irregular arrangement of molecule is high this structure is known as atactic structure this structure is known as atactic structure and their physical property is not good and hence they are not useful okay this structure is known as atactic structure their physical property is not good hence they are not useful next line to get regular arrangement to get regular arrangement we use a catalyst called jigler netta catalyst to get regular arrangement we use a catalyst called jigler netta catalyst can you move on yeah the last thing here we have to discuss this chapter is write down resins what are resins anything you know about resins what are resins some plant product plant product you must have seen on the tree there is some yellowish orange color semi liquid substance is there some tree I have seen it I don't know whether you have seen it or not so it is semi solid it is not completely liquid not completely solid you can you know change the shape also easily by applying some pressure on it that is not a big deal so that yellowish or orange color liquid that you have obtained from the tree those things we call it as resins okay the examples of resins are the first example is beccalite okay beccalite is an example of resins you see this it is actually the product of or the monomer of beccalite is phenol and formaldehyde formaldehyde and hence the we also call it as phenol formaldehyde polymer okay or phenol formaldehyde resins beccalite is nothing but phenol formaldehyde resins okay so this reaction actually reaction between phenol and formaldehyde it takes place in both acidic and basic medium mechanism like I said it is not required I will just discuss little bit here H plus OH minus and it forms ortho-parasubstituted product which is OH and here we have CH2 OH ortho-substituted product and para-substituted product is this OH and CH2 OH now the reaction takes place at both position ortho and para these two reacts OH CH2 OH reacts with CH2 OH reacts with CH2 OH OH so this actually and in acidic medium this goes out at H2O it combines and gives this product OH ring here we have CH2 OH CH2 this also goes this way like this we will get a long thin compound this kind of reaction is possible at this position also so overall you can get this product it is a very complex reaction I am not writing down the entire reaction here you get something like this OH we will have here and we get CH2 this is also attached with CH2 OH and this CH2 attached with this there is an open bond here CH2 this side this structure the entire complex structure is nothing but beccalite structure is not at all important this is used for the production of pressure cooker handle and it is a cross linked thermosetting polymer it is a cross linked thermosetting polymers thermosetting polymers means what when we heat this cross linking takes place which does not break down on cooling that is why it does not become soft again the other examples of resins are phenol formaldehyde we have seen already the other one is melamine formaldehyde polymer just name you write down melamine formaldehyde I will write down the names other examples of resins are melamine plus formaldehyde and one more we have urea plus formaldehyde all these are examples of resins melamine structure you must remember this has been asked in JEE exam the structure based question of melamine here we have NH2 NH2 here we have NH2 and double bond like this this is a structure of melamine question that they ask how many lone pairs are present in melamine can you tell me the number of lone pair in melamine number of lone pairs in melamine is it 6 yes 6 6 lone pairs one lone pair on each nitrogen atom the exact question they have asked in JEE exam but they haven't given the structure of melamine the name they have written the question has count the number of lone pair present in melamine structure you must know because when the structure is given there is nothing to do in this ok so this is it for polymers polymers is done let me see if one or two things are there one question we will see we have done it ok this is it for polymers what should we start next shall we start surface chemistry so you can finish off nucleic acid nucleic acid last class in biomolecules I have discussed that average molecular mass how to find out those things the formula is there have you finished that average molecular mass percent is and then in the last you gave the formula it was the last yeah we have done this ok so we will do nucleic acid nucleic acid do you have NCRT book with you now yeah open it what is the content given in nucleic acid tell me the topic name chemical composition of nucleic acid structure of nucleic acid this is again chemical composition is given then structure and biological functions structure of nucleic acids and biological functions right there are few structures what is the name of the structure given they are given perimidine cytosine, uracil thymine adenine those structures actually you have to again memorize sir is nucleic acid very important from JEE point of view I don't think it's very important because it is mainly you know important for NEET experience structure based questions replication and all they won't ask in JEE structure of compounds that you have that you should know like the all name that I have taken that you should know like the heredity the genetic code and all that is not required for JEE so what is important here is to know the structure of the different molecules adenine guanine those things like I told you just now melamine they have asked number of loanwares and all so like that they have they can give you some name of the compound in integer type questions find out the the loan pair present in thymine this kind of question they ask structure based question they ask function wise they don't ask because that is then goes to the NEET the biology things and all okay so you see here we'll just finish it what is the nucleic acid see when we talk about the living cells okay these living cells contains nucleoproteins okay now these nucleoproteins are actually forms by the combination forms with proteins actually in combination with biopolymers of another type of nucleic acids okay so actually the nucleic acid has it has there are two types of nucleic acid you know that DNA and RNA right what is the DNA what is the full form of DNA deoxyribonucleic acid deoxyribonucleic acid okay RNA is ribonucleic acid so the nucleic acid is actually write down I'll go to the next page here structure of DNA and RNA you can go through the book it's a complex structure helical thing and all that you can go through it is not required here I won't draw it it's very complex it's very difficult to draw also okay that is structure you can go through what our link is all there I'll explain that so open the book and look at the structure when I was when I was spinning it okay I'll tell you so nucleic acids are what these are the compounds write down which are made up of compounds which are made up of proteins with the biopolymers of with the biopolymers of another type of compounds so proteins and biopoly another kind of biopolymers if they mix it forms nucleic acid so the mixture of proteins and other types of biopolymers okay it is of two types like I said DNA and RNA DNA is C ribo nucleic acid and RNA is ribonucleic acid ribonucleic acid okay next line these are basically long chain polymers of nucleotides okay it is basically the long chain polymers of nucleotides next slide down the chemical composition of nucleic acid chemical composition of nucleic acid write down hydrolysis of nucleic acid whether you take DNA or RNA both hydrolysis of this hydrolysis of this gives pentose pentose sugar hydrolysis gives pentose this is what you need to memorize so when you go through the NCRT these kind of information you must keep in mind okay pentose sugar okay see there are two types of heterocyclic nitrogenous base present in this molecule like you see the structure there are two structures we have the basic thing is pentose and pentose structure we have already discussed in the fructose thing right so the structure of beta D ribos which is used in ribonucleic acid I will draw here so I will draw the structure and write down the name and it is a three dimensional structure three dimensional structure so this bond this carbon is actually coming towards the observer this one this is coming towards the observer at this carbon we have OH on the top H on the bottom here we have H on the top OH on the bottom H on the top OH on the bottom H on the bottom CH2 OH on the top this structure is beta D ribos ribos and it is used in RNA ribonucleic acid another structure you draw which is the exact structure this you draw here oxygen again it is coming towards the observer just a second at seven BR2 C4 at seven BR2 okay so it is then BR2 or BR C4 at seven so eight into ten so it is a dialect there are many structural possibilities C4 at seven BR2 you said okay Param you give me some time because I am in class right now I have class till one o'clock after that I will send you just drop me a text on whatsapp I will send you okay after one o'clock I have class till then okay huh so the structure is beta D ribos and beta D deoxy ribos okay so this one is beta D ribos we have drawn this one is beta deoxy ribos the structure here we have OH and this side we have hydrogen this carbon has two hydrogen is this a structure given in NCRT can you check once OH H here and here we have hydrogen CH2 OH it is given sir this structure is correct no this carbon has two hydrogen yeah the name of this compound is beta D ribos sorry deoxy ribos deoxy ribos in DNA these two structures we have so pentos actually it has the reference compound is pentos only which has this ring which exist in these two form in DNA and RNA okay so there are two base actually here like I said the full hydrolysis of DNA and RNA gives a pentos sugar okay ribos in RNA and deoxy in DNA deoxy ribos in DNA two kinds of heterocyclic nitrogenous base is present in it okay the base that we take okay one is they give pentos sugar and other one that we get here so the pentos sugar structure I have drawn two types and the other one we get on hydrolysis on hydrolysis it gives two kinds of heterocyclic nitrogenous base right down to heterocyclic nitrogenous base I am just giving you the the chemistry aspect of it the reaction of it nitrogenous base okay that we call it as the two nitrogenous base that we get here is purines and pyrimidines purines and pyrimidines and apart from this apart from this we also get phosphoric acid this is what you need to memorize the product phosphoric acid now the important thing here that you already know we have done this in biomolecules this is first carbon right one two three four and fifth here also same thing one two four and fifth what you have to keep in mind that C2 carbon in this deoxyribose C2 carbon does not contain OH group this you must remember it is not present at C2 carbon okay now these two structure you must know pyrimidine and purines okay next one we will draw the structure of these two pyrimidine structure is this we have a ring nitrogen structure of pyrimidine alternate double bond and I will write down the name here pyrimidine and another one is purine purine structure is similar to pyrimidine which is this oh I missed one thing here we have nitrogen here we have nitrogen so pyrimidine we have this structure two nitrogen atom here also we have nitrogen atom one two and three so pyrimidine is this so this is also pyrimidine but apart from this we will have a five membered ring here which has one nitrogen present here another nitrogen present here and these two are attached like this so five membered ring here so we have a double bond here and then nitrogen we have here so one hydrogen this side this structure is purine okay I will draw two three more structure into this because you see what happens in pyrimidine it has a single heterocyclic ring pyrimidine is this single heterocyclic ring and purines have two ring fused ring we can say one is this five membered ring and this six membered ring two fused ring we have so DNA that deoxyribose nucleic acid DNA has the purine base and pyrimidine base both base will have in DNA but not exactly the same molecule but the base of this the purine base is adenine and guanine which is present in DNA and pyrimidine base is thymine and cytosine which is present in DNA but in RNA it contains uracil instead of thymine in RNA we have uracil present not thymine is not present over there and it is important to note that there are two key structural difference between DNA and RNA okay DNA contains deoxyribose while RNA has only ribose sugar that's what we have discussed last page only the difference between DNA and RNA the main difference which is a very important point here DNA has thymine while RNA has uracil okay so that's what we will write now first we will draw these structures of adenine uracil thymine guanine you should know all these structures okay so with pyrimidine you have three different base we get here with respect to this the reference compound is this and with this we will get three different bases the first one you write down from this only this way from pyrimidine the first one is this we will have a a six membered ring here we have double bond O and alternate double bond is not present in the ring we have a double bond only here okay so C-H double bond C-H this double bond O and we have H here and here also we have NH trivalence you have to complete this compound we call it as uracil the structure you must remember name is not enough because once they have asked melamine they can ask you any one of these structures also uracil is represented by the symbol U now this one we have cytosine cytosine the difference is what instead of this C double bond O we have NH2 present here so the structure is this NH2 this is the structure of cytosine represented by capital C one more structure we have and that is thymine thymine is everything is same with respect to this if you see but the only thing only difference is here we do not have one hydrogen but one CS3 present onto this carbon structure is this nitrogen we have here double bond O here we have double bond here we have CS3 NH and NH this structure is thymine that is T this is the structure of the three bases of pyrimidine which is present in DNA purine the two base we have that is adenine the structure is this we will draw this structure with NH2 over here so the structure will be this and double bond here double bond here and double bond here this carbon has NH2 and this is attached with one nitrogen so we have hydrogen here and double bond here okay hydrogen double bond and this structure is adenine it is A and in Goa 9 the structure is just you write down this structure in Goa 9 here you write down C double bond O this Goa 9 is important here we have C double bond O and here we have NH2 double bond double bond nitrogen hydrogen here and this will be as it is nitrogen this side and both are attached with double bond CH hydrogen we have here this structure is Goa 9 that is G finish this structure let me know I will just give you 2-3 points here done sir write down pyrimidine contains pyrimidine contains a single heterocyclic ring pyrimidine contains a single heterocyclic ring while purines have two heterocyclic ring fused together purines have two heterocyclic ring fused together you see this is the two ring we have no two heterocyclic ring this is one heterocyclic ring another heterocyclic ring two heterocyclic ring fused together DNA contains DNA contains The purine bases in bracket you write down adenine and guanine DNA contains the purine bases in bracket write down adenine and guanine while purine bases adenine, guanine and pyrimidine bases in bracket thymine and cytosine. So uracil is not present in DNA okay and pyrimidine bases thymine and cytosine okay so uracil it is not present in DNA. Next line RNA contains RNA contains uracil instead of thymine okay RNA contains uracil not thymine. So this thymine it is not present in not present in RNA this is the another point okay all these compounds that I have written uracil cytosine okay thymine. All these are bases right and it gives nucleoside means nucleoside of adenine is adenosine okay how do you get nucleoside nucleosides are the n-glucosides of purine and pyrimidine bases okay just you write down next point I will draw the structure you will understand this. Write down next line nucleosides are nucleosides are n-glycosides of pure of purine nucleosides are n-glycosides sites of purine or pyrimidine bases with pentose sugar. So this is the definition of nucleoside pentose sugar what are nucleosides we have a pentose sugar and that is linked with purine or pyrimidine base with n-glycosidic linkage okay so what do you mean by this n-glycosidic linkage. Suppose if I draw the structure of sugar here which is this this is a structure of sugar I won't draw the entire thing here right so we have all these bonds present OH etch you can put it on here CH2 OH like this we have here. And this carbon this C1 actually it is attached with the base like this nitrogen and then the ring we have like this okay write down here base and base so this link is what this link is the n-glycosidic bond n-glycosidic bond. So these are nucleosides actually so when you take adenine as a base the nucleoside is adenosine so with base what is the name of nucleoside we have I'll write down here base one side and the name of nucleoside this side so if the base is adenine nucleoside is adenosine. If the base is guanine nucleoside is guanosine citosine it's citidine thymine thymidine uracil it is uridine. So the point is this reference compound is pentose only this is not going to change but base can be changed if the base is this corresponding nucleoside is this the name I have written. Similarly, nucleotides are what the last thing here we discuss is nucleotides. Okay, structure of DNA is a double helix structure that you can go through. Okay, structure of DNA. Okay, so this is nucleosides you should know. Next we'll discuss is all of you have written this. Yeah. Okay, similarly nucleosides like I discussed it is it is the you know the combination of purine or pyrimidine base with pentose sugar and this base and sugar is connected with and glycosidic linkage nucleosides is this similarly nucleotides also we can define. Okay, so what is nucleotide right now. Nucleotide is a phosphate ester of nucleosides a nucleotide is a phosphate ester of nucleoside, which contains a purine or pyrimidine base, which contains a purine or pyrimidine base with five. Right now like this purine and pyrimidine base with a sugar with a sugar contains five carbon atom. Okay, one thing I'll repeat here. In the last page that this structure is this structure is a base it is not the actual structure I have just drawn this to make you understand what is and glycosidic bond. So this is adenine base you're taking. So here we have the structure of adenine guanine, then the structure of guanine so this is just a base where this end bond is joined with this carbon. So it is not any, you know, correct structure is this is not the correct structure, because we have two nitrogen present in the ring all these if you see. What the meaning of this anyways, so next thing is what this nucleotides like I said it has one base. Right, purine or pyrimidine base plus five membered sugar plus phosphate phosphate and then it forms nucleotide. Okay, if I draw the structure here of a nucleotide, the structure will be like this. Okay, see one carbon. We have hydrogen here. And this contains one, like I said one base. So this is the base I am using here double bond O. Here we have double bond. Here we have double bond. And here we have NH2. So this is one base we have connected with C1 OH H. This is the sugar we have pentos. So OH H and here we have HCH2 OH we have in general, but it is connected with a phosphate. So this point, it is linked with a phosphate ion, which is P double bond O minus single bond O minus. So phosphate, sugar, five membered ring and a base. This thing is nucleotides. Okay, so base is there. This one is sugar. And this one is phosphate. They won't ask you the structure. You should know the definitions of nucleotides. However, this is also not that much important. Okay, one note you write down, nucleotides are linked together, nucleotides are linked together by phosphodiester linkage, phosphodiester linkage between fifth and third carbon atom of pentose sugar. Okay, this is the last thing you have to keep in mind. The structure also you can draw two phosphate group you have to attach at fifth and third carbon, okay, on pentose sugar. Like you see, here we have this group attached here. Okay, one more if you attach this side. Okay, this gives you phosphodiester linkage. Here, same this group present at this carbon, third carbon. This is third and this is fifth carbon. So this is the, you know, way the nucleotides are linked together. This is one nucleotide molecule. At this point, the another nucleotides are linked. Okay, so like that you'll get a very, you know, big complex structure. NCRT, I don't know whether it is given or not this structure, but all these things you don't have to draw, you should know the key points that have given you that nucleotides are linked together by phosphodiester linkage. This term is important, phosphodiester linkage between third and fifth carbon. Okay, so this is it. After this, we have function of DNA and RNA, which is not required, but I'll suggest you to go through once through NCRT. Okay, that is more than enough. Okay. Yes, sir. This is done. I think it's there. Okay. So, what we do next, we have half an hour more. Tell me, any doubt you have? No doubt, sir. Okay, one question you solve then. One last question, we will finish it early today. Not from this, some other things you'll see. Did you write the test yesterday? The escape, I guess? Yes or no? Yes, sir. One question was there. Let me give you that question. Wait. So there was this one question as to Friedel Kraft's alkylation, what it means. What? I said there was this question in the test that Friedel Kraft's alkylation is and then four options. What are aromatic nucleus and... Do you have that question now? One minute, I'll try pulling it. You have your phone with you right now, all of you? Okay, let it be. I'll write down the question here. See, the question is 2.52 gram of hydrated oxalic acid. Hydrated oxalic acid is oxalic acid with 2H2O. Hydrated oxalic acid was dissolved in 100 ml of water, 100 ml of H2O. 10 ml of this solution was diluted to 500 ml. Find normality of the final solution. Normality and the amount of oxalic acid present in the final solution. Do this. What is the answer you got, Shreya? That 0.08 thing. Did you get the option right? Yeah. Oh, do it now? Shreya, the question is there... It was dehydrated and not hydrated. The question is there dehydrated. Okay, but with dehydrated it means the molecular mass should be what? 63. It should be 19, right? Dehydrated means what? I have given you hydrated oxalic acid. Okay, I did not check this because the solution was given over there. The solution, the molecular mass they have taken as 126, correct? Yeah. 126. But in the question, they have given dehydrated. So when it's dehydrated, it means the molecular mass should be what? 90? Oh, I switched both, sir, by mistake. That's why I am getting the answer. Yeah, so when you get this dehydrated oxalic acid if you take... Okay, then the answer will be something else. It is not there in the option. Okay, answer is something else which is not given in the option. So you try this. Hydrated means molecular mass is this? Number of equivalents will be what? Mass divided by equivalent mass? 2.52 divided by equivalent mass E. So equivalent mass of oxalic acid is what? If it is hydrated, I am going through the option. So through the solution which is given. Okay. Taking this as hydrated. 2.52 divided by 126 divided by 2, n factor is 2 for oxalic acid. Okay. This you will get this by 63, that will be 0.04. Yes or no? No, sir. 0.08 only. So number of equivalents will be what? 0.04 divided by 100 ml into 1000. That will be 0.4. This is 0.4. Now we use n1v1 is equals to n2v2. So n1v1 is 0.4 into volume is what? 10 ml of this solution is valued. So into 10 and 2 into volume is 500. So when you solve this n2 you will get 0.008 which is not there in the option. Okay. Yeah, but I thought it would be the closest like this 0.108. So that's why I am asking. Fine. No issue. So this is a normality you'll get and this normality when you try to find out the mass is equals to equivalent by volume of solution is 500 into 1000. So number of equivalents you'll get here is around 0.004 which is mass by equivalent mass of oxalic acid 63 and this is coming to be around 0.252 gram which is not there in the option. Okay. So this we get when you are taking molecular mass is 26 and for this the question should be hydrated oxalic acid. This is one thing. Correct. If it is dehydrated then molecular mass is what 90? Okay. So this will get here what for dehydrated if you try to do then the number of equivalents is what? Number of equivalents is 2.52 given mass divided by the equivalent mass and that will be 2.52 divided by 90 divided by 2. What is this value? 0.056. 0.056 you are getting. Okay. So normality is what? 0.056 divided by volume is 100 into 1000. This will be 0.56 normal. Correct. Now 0.56 into 10 is equals to 500 into N2. N2 is what? 0.56 into 10 divided by 500. What is this value? 0.011. 0.011 which is again not there in the option. Right. I don't think 0.011 is there in the option. Is it? No. So that's why the answer was wrong. Okay. I think the when you look at the data. It should be hydrated oxalic acid. Then you see this equivalent weight is getting canceled and we are getting proper 0.04 equivalent here. 63, 252 by 63. So it should be hydrated oxalic acid. Tell me anything else? Anything else? No, sir. So then we'll wind up. Okay. Yes, sir. Okay. Okay. See you tomorrow. Probably we'll have a class most probably we'll let you know by evening and we'll start P block tomorrow. Okay, sir. Okay. Thank you. Thank you. Thank you, sir.