All Reaction Mechanisms in One Shot – MDCAT Chemistry Live Class | Sir Naved

[00:00:00]Assalam Walekum students. today's class As all of you children demanded.

[00:00:04]that we should be taught reaction mechanisms In the shot. So I will fulfill your wish I will not do it. could be possible. So today's class In this we will talk about the reaction mechanism And we are going to discuss the reactions of organic chemistry.

[00:00:18]We will look at the mechanism and read it in detail.

[00:00:21]And every small and big thing can be handled easily.

[00:00:25]Will try to understand. Ok? So today's In class we are going to discuss to methane. We will discuss this with Nucleophilic Substitution Reaction SN1, SN2 and electrophilic addition of benzene Substitution reaction. So I hope you Will you be ready and yes I hope for today's session You may experience any reaction again later.

[00:00:47]The mechanism can be seen sitting here and there on YouTube.

[00:00:50]No need to search. all the things I will do it with you today and this is one of the The best lecture will be on mechanisms on YouTube In. Let's start. doing Bismillah Are. Let's start son, we're halogenating of methane. But before that, a few things I have to teach you, explain to you. Let go I understand. we would have chemical species Are. As ions are, molecules There are atoms. Similarly, our There are also pass radicals. What are they?

[00:01:19]Radicals. Let's understand radicals.

[00:01:23]Well, radicals you also have ionic radicals in which you have cation anion Let's go. Correct? and free radicals What is the purpose, son, of free radicals?

[00:01:32]It means that one of you has let Suppose there is a bond between a and b.

[00:01:39]Ok? Now there is a single bond, so one electron will belong to it and one electron What will happen to what might be happening between them?

[00:01:46]Must be sharing. Correct? If Bond something Break it down in such a way that the shared pair is equal It should be distributed. Meaning if two electrons are being shared so one of its near and one near it.

[00:01:58]The breaking of such bonds in which Electrons should be distributed equally.

[00:02:03]Kids, we call this homolytic.

[00:02:06]Bond breaking or homolytic cleavage.

[00:02:09]What do we call this? Homo Lytic Cleavage of bonds or bond breaking.

[00:02:19]Ok? The bond was broken at par. Whose He took the electron. Now this case In 2015, no atom gave up its electron.

[00:02:26]Neither did anyone lose nor did anyone gain. So now here But ionic species will not be formed but like this chemical species will be formed on which no The charge will not be present. Is this radical?

[00:02:38]Who do we call a radical, son? of radicals Meaning we take two meanings. If I told you Go Radical So you should understand that either it is being said odd Electron species.

[00:02:52]chemical species that have electrons The number is in odd numbers. 1 3 5 7 Okay?

[00:02:59]Or it is also said that such Chemical Species Having Empty Valency yes. Have empty valency.

[00:03:10]Ok? an empty valency if it has If it exists then I would call it radical too.

[00:03:16]And technically radical odd electron There are also species. This means no octave Neither the duplicator has been completed because Octet duplet both are even numbers Obviously. And what is meant by empty valency It is also true that one of its valencies is vacant. These There is no stable molecule. the reason for which So radicals would like to react.

[00:03:36]That's Why Radicals Are Radicals Are Reactive species. what are radicals Are? There are reactive species. So this I understand your point about free radicals.

[00:03:46]What are they? Ok? free radicals What are they? that whenever the bond is broken homolytically How did it break? of electrons broken apart by equal The distribution should be equal or shared.

[00:03:57]Both should be paired and distributed equally.

[00:03:59]Between the atoms. So the bond that will be broken It will be called homolytic cleavage. and its consequences Whatever I make, son, we will call it free Radicals.

[00:04:11]And radicals are odd electron species.

[00:04:15]You have understood this much. very simple thing Is. Ok? Now the question is that free radicals What is a substitution reaction? Now I will explain to you after free radicals.

[00:04:24]What is substitution? Substitutions It means son replacement.

[00:04:28]If one goes, another comes. For instance.

[00:04:31]For example, A and B had a bond. C came and C replaced this B.

[00:04:39]Bond is formed with AC and B goes out.

[00:04:44]Are you getting the point? This is called Replacement. Removal of A and replacement of another.

[00:04:48]Like, for example, I'm sitting on this chair.

[00:04:51]I am sitting. I will step aside and Sir Akbar will come.

[00:04:53]Go. Ok? So what will happen? Replacement It's done. Sir Akbar replaced me.

[00:04:58]This type of reaction is called Substitution. And there is another edition. Correct Is? That I am sitting here. Sir Akbar also Come and sit next to me. will call it Edition. That I didn't go anywhere. My Someone else also came into presence. So I make it I would say edition. I understand the substitution thing Is? One will come and the other will go from here.

[00:05:15]Now the important thing to note is that if free If there is a radical substitution, then there is also the coming one.

[00:05:21]Son, there must be a free radical and outside which Whatever comes out will also be a free radical. means this that substitution substitute always like that for example if there is cricket But if a batsman has to be substituted If so, then a batsman will come in his place. If If a bowler has to be substituted then his Only the bowler will come in his place. If you have a refrigerator at home If you want to replace the refrigerator, then replace it with something else.

[00:05:45]You will bring a better and stronger refrigerator. Isn't it?

[00:05:47][sound of clearing throat] It's not like that Will you buy a washing machine tomorrow after giving me the refrigerator?

[00:05:51]We will keep the meat in this. It is not like that will be. So whenever the replacement happens The one who is replacing him is getting replaced.

[00:05:58]It should be of the same species. Nucleophile will replace the nucleophile.

[00:06:02]Will replace electro file Electro file. free like this Free radicals will replace radicals.

[00:06:10]Did you understand what I said that free What are radicals? How free radicals Are they made? and free radical substitution What does reaction mean? a free radical What should be done to the other free radical?

[00:06:24]Substitute it.

[00:06:27]Ok? reaction of one free radical with another free radical What should be done to the radical? Substitute Tax Give. What is it called? free radicals substitution reaction and as I Said you know when the Saranvedas come I will tell you everything and then leave. Now additional Listen to some things that you might have If you haven't heard it before, let us hear it now. To all Firstly, homolytic fusions such as I told you when the bond breaks homolytically Okay, so what will you make? free radicals but When will homolytic fission occur? When Ultraviolet light will interact with any with the molecule and what that bond should be like Normally, what should that bond be like?

[00:07:05]Needed? Must be non-polar. So non polar Bond when in the presence of ultraviolet light If there are breaks in the free radicals exist Come in. Brother, this is not the point. This is the thing that free radicals are electron-losing species There are. Sir told. next thing give Reactive species. Sir told. De R Neutral. There is no plus or minus charge on these.

[00:07:27]It does not happen because electrons are equal are distributed when the bond breaks Is. Sir told. Now let's talk about the next thing Paramagnetic in Nature. This is a new one for you It has been said that radicals are Radicals have what they call unpaired Electrons are present. Is Unpaired because of the electron like you have Methyl free radical. What is its nature?

[00:07:48]It is not diamagnetic. These It is paramagnetic because it has electron Unpaired ones exist. An unpaired electron due to which it is Will he behave like this? a paramagnetic Paramagnetic Will behave like a species that lives under Strong magnetic field these attraction shows Will do. Ok? That's why it is Paramagnetic sp paramagnetic in Nature. The next thing is as written here That the CH3 that you have is is paramagnetic but the carbon hybridization is here as you You would know that methane is made from methane.

[00:08:26]methyl free radical of methane Hybridization because the alkene is sp3 There will be CH3 which is a radical, its What will be the hybridization beta sp2 You also know the structure here.

[00:08:41]will be tetrahedral and here it will be trigonal The plane will be inner. You understood this much.

[00:08:45]Ok? Did you understand this much, children? Correct Is? I understood very well what radical is.

[00:08:50]Are there? When are radicals formed? and radical what characteristics, what specialities Are there? If you have understood this much, So now you are ready to study a topic.

[00:08:59]For this we call it halogenation of methane.

[00:09:02]What do we call this? halogenation of Methane. So you are absolutely right in understanding that Halogenation of methane is free radical.

[00:09:16]Substitutions Reaction. You understood it absolutely right. that's why I told you about free radicals.

[00:09:25]What is halogenation of methane, son? These It is a free radical substitution reaction.

[00:09:29]in which one free radical is converted into another free radical What will he do? Will substitute. So much I understood the matter. Now let's understand one more thing that halogenation of methane and alkane is a Successive Replacement of hydrogen atoms of methane and alkane With halogen Atom.

[00:10:19]Ok? What will happen? Successive replacement that one hydrogen is removed from its A halogen will come in place. Then one will remove his Another one will come in return. Then one will be removed and another Will come. So this is a successful replacement.

[00:10:30]Ok? There is not one H that all four H will suddenly fly away. No. One will be removed, one Halogen will come. One hydrogen will be removed. This Is called the successful replacement. one of after a. You understood this much. Very It's a good thing. You are getting the point.

[00:10:45]Look what happens is you have methane.

[00:10:48]You get it reacted with Cl2. Because This is a free radical substitution reaction.

[00:10:53]So here you sunlight means ultraviolet You will talk about light here. Yes, Halogenation of methane, son, that dark It happens in me too. Even without light goes. Ok? Even in a dark room Will go. But then you have to pay high for that.

[00:11:07]Temperature and peroxide can be measured as It will happen only if you use catalyst. Here But I use ultraviolet light.

[00:11:14]I have been. Explaining the free radical mechanism For. So what will happen? One hydrogen will be removed Son.

[00:11:21]Ok? CH3 will be done and will come to you Cl. The H that will be removed from here, son, will be the second one.

[00:11:27]It will combine with chlorine to form HCl.

[00:11:30]This is the reaction you have. Right now I I move on to the mechanism. Ok? This is it You have a reaction. Now understand one thing. One Understand clearly that ultraviolet Light is the reaction to the reaction Will just initiate. What will he do?

[00:11:44]Initiate. The reaction will continue on its own.

[00:11:47]I mean, what do you do? Take methane, chlorine Put it in. Take it closer to sunlight. Sunlight Will have to. The reaction will begin. Now you Bring it to the dark room. The reaction itself is Dutch will continue doing this. Ok?

[00:11:59]So it is also understood that ultraviolet The work of light is to initiate. Reaction It can also move forward on its own. Ok? Meaning Once you initiate, darkness in sunlight Bring it to the room, things will get sorted out automatically.

[00:12:10]What will happen is that another hydrogen will be removed. CH2 Sorry CH3Cl another Cl2 then what will happen? CH2 Cl2 and a and HCl This reaction will continue until then, children.

[00:12:26]Until what happens? all the hydrogen If it goes away, what will it become? Carbon Tetrachloride CCL4 is formed. I understand the matter Is it happening? until the reaction reaches here He won't stop until he doesn't go. Now The important thing to note here is that the product When will it reach here? When you combine halogens You will use it in access.

[00:12:48]What does halogen have to do with it? Use in Axis Have to do it. That is why we say the Extent of halogenation. What is meant by extent To what extent will the reaction occur? Extent of halogenation It depends upon amount of halogen used Where will the reaction stop? Reaction How far will it go? what is the extent of the reaction Will it happen? On whom will this thing depend, son?

[00:13:27]How much halogen are you using? So halogens If you use it in access then you will get You will get the product, son, in the end that CCL4 will get. And because there are four Reached after steps. so often In MCQs you can give that if What if chlorine is used in access?

[00:13:44]Will you get it? With CCl4 you get 4 HCl will get. One HCL will be available in each step.

[00:13:48]There will be an HCL here too. This is also the most It's likely that you have a product when You used Cl2 in access to that product What if you have CCL4 and HCL 4HCl I was talking about the reaction. Now Where will I grow, son, in the mechanism of its mechanism okay its mechanism Let me discuss the earlier reaction Of The mechanism of this first reaction What is it, now I started moving towards the mechanism.

[00:14:17]hmm ok See when will the reaction start? when did I What did you say about when to initiate a reaction?

[00:14:24]will be?

[00:14:29]Initiation The reaction begins. What did I say?

[00:14:33]When will the reaction begin? When you're in the sunlight Will you keep it? Ok? Who will you keep in sunlight?

[00:14:37]A mixture of methane and halogen. what did you Did you do it brother? You took this container. This container you put methane in and you put Cl2 and put both of them under sunlight.

[00:14:49]You kept it. Now here are two molecules.

[00:14:52]You have it. carbon in a molecule and hydrogen bonds and other molecules There is a bond between chlorine and chlorine. Now The first bond to break is the weak bond.

[00:15:02]will be. Isn't it? Weak things would break first Are. So the bond energy, son, is bond Energy is what defines bond strength She does. The higher the bond energy Ok? The higher the bond energy The same molecule, the same bond What will happen? Will be strung. So the bond energy Since carbon and hydrogen bonds is more and chlorine chlorine which Bond is weak. Low bond energy it occurs. So which bond breaks first?

[00:15:30]Is it son? of chlorine. So what happens Initially, you have chlorine.

[00:15:42]Okay, you have chlorine.

[00:15:47]In the presence of sunlight, this bond is will break okay and you'll get two radicals okay We don't show all these electrons.

[00:15:58]Make a small zero on top and make a knot bond.

[00:16:02]Give it, make it O whatever you want to call it. So this You would call this radical. What is it made of?

[00:16:06]From chlorine. I would say chlorine Free radicals.

[00:16:13]Now all those things will apply to this.

[00:16:15]Son. If it is a radical then odd electron species It will also be reactive, paramagnetic It will also happen. All these things are the same Will apply as I told you.

[00:16:25]Listen to the next thing. Because ultraviolet This reaction occurred in the presence of light. You If you give energy then it happens. So this means initiation.

[00:16:34]The step which is there, son, is the initiation step.

[00:16:39]Let me write it down completely. Why write A completely?

[00:16:42]You will understand the matter. It is endothermic.

[00:16:46]Ok? The initiation step is endothermic. These It is endothermic. If heat is absorbed The bond will break and further radicals will be formed. These You understood the point. Listen to the next one too That there were no radicals earlier. After the reaction Be radical. This means in this step in this step number or there is net increase in the number of Free radicals.

[00:17:28]Correct? This is the step in which the radical The number is increasing. First, even a single radical Was not there. Earlier there was not a single radical.

[00:17:34]After the reaction, two radicals came brother. So How would you define initiation? You would say initiation is an endothermic step in This step there is a net increase in the number of free radicals. Ok? You chain it You can also call it initiation. chain reaction of Where does it begin? From Initiation. Correct Is? I understood this much and as I Said that all these things will apply of chlorine that you have You have free radicals that are reactive as well.

[00:18:03]There will be an odd electron species as well.

[00:18:05]It will also be paramagnetic. Ok? Bus The matter of structure applies only till CH3 Will happen. Hybridization and structure.

[00:18:12]Do not apply here. Ok? So this I understood the point. The reaction that is I have been initiated. Became a radical. Reactive It is a species. Now listen further.

[00:18:20]The next step is called beta chain propagation.

[00:18:24]Step Number Two Chain Propagation. Now this chain will propagate It will spread.

[00:18:39]Ok? It will spread brother. will what? Understand brother will what? This is the chlorine radical formed which is a reactive species. These are your Who will look at it equally? You have this Chlorine was mixed with what?

[00:18:52]Son? You mixed it with methane.

[00:18:54]So what will he do? in his own right Will see. Show him brother Mithen. methane here I was roaming around there. It said oh yes because I am a reactive species. React React I found someone to do it with. So as if I told you that a radical replace Will do it to another radical. It means that What will happen is that chlorine will take out this H Will take it out.

[00:19:18]Ok? And HCL will make it for you.

[00:19:22]Plus Because radical will replace radical So this is what was left behind CH3 Okay, this is going to be another radical.

[00:19:34]A radical will come in return because This is methyl, so I would say methyl free.

[00:19:41]radical methyl free radical Now this methyl free radical, this Methyl is a free radical, it will come from this brother Angry at how my hydrogen was taken away Brother chlorine? How did you take it from us? So now He got angry. This will cause chlorine Later he will ask, brother, how did you get hydrogen like this?

[00:20:01]Now let me tell you. So this chlorine Sorry, this is the free radical formed by methyl is also an odd electron species. This too It is a reactive species. So what will he do? These To whom will he run? a chlorine near another molecule. that hasn't broken yet Is. Ok? What hasn't broken yet. What It must be that this is a free radical of methyl This will remove the chlorine and create CH3Cl Plus this Cl now becomes chlorine.

[00:20:29]Free radicals. One radical went, another radical Came into existence. Ok? So replacement of It became radical. Free radical substitution is Went here. Are you getting the point? Now this which This is again methane, a free radical of chlorine.

[00:20:44]will go to another molecule and this Will repeat the reaction again. thats Why it is called chain propagation. a chain The reaction will start from here. Correct Is?

[00:20:55]If you pay attention here, you will see That there is a radical consumption happening here.

[00:21:03]molecule is being formed, then in return a He is also leaving Radical. if anyone The radical is converting into a molecule.

[00:21:10]If it is being consumed then a radical in return He is leaving as well. one for one If one goes and one comes, there is no difference in the number.

[00:21:17]Will have to. This means in train propagation Meaning in this step ok in this step there is no net increase No Net Increase or Decrease In the number of free radicals. This is that step in which there is no increase in radicals It will happen and there will be no shortage. Number of free Radicals.

[00:21:55]You have understood this much. What will happen? Here Radical on It will also be consumed.

[00:22:03]Meaning, radical consumption is also included in this step.

[00:22:06]will be. Ok?

[00:22:10]And also the form will be made. So this thing I understood that one would be consumed and one would be exchanged.

[00:22:15]It will be made in. Ok? Now the next thing I tell you is I will tell you that this is the step you have.

[00:22:20]It is exothermic.

[00:22:23]What happens son? It is exothermic.

[00:22:25]Ok? Now this is the step you have.

[00:22:28]It is exothermic. Butt is an attention-seeker The point is, what is exothermic for?

[00:22:32]Very highly exothermic for fluorine It happens. In addition to chlorine, Same for bromine. But iodine for these What is the propagation step?

[00:22:42]It happens? Endothermic like the first step It happens. Ok? Why does it happen? How It happens? I won't go into the details right now But yes, if you want, then remember that This step is exothermic but for whom?

[00:22:52]for fluorine, for chlorine and for bromine. Ok? And yes, and more I will tell you many things. So Listen carefully and understand Stay, keep absorbing. And if someone If you have any question then please comment in the comments.

[00:23:04]Keep typing.

[00:23:06]Ok? Now we talk about propagation.

[00:23:10]Took. Now let's move on to the next step, son.

[00:23:12]what we call termination or chain Termination.

[00:23:19]Chain termination or simply you can also call it termination You can. Ok? What happens at termination?

[00:23:24]Is it son? Watch when two radicals combine There will be radicals, not radicals and radicals.

[00:23:29]If they meet, what do they create together?

[00:23:31]Let's make a molecule. such as the example As a chlorine radical of chlorine What will combine with Radical and what will it create Son? Cl2 will be formed. radical of methyl and methyl radicals will combine with each other and what Will you make it? will form ethane. Isn't it? Methyl radical of and chlorine radical if found If it goes, it will form methyl chloride.

[00:23:52]So yes, keep this in mind that only The product is this reaction that takes place CH4 + Cl2 gives CH3Cl + HCl so these two The product is formed but along with it Cl2 It will also be made. Along with this CH also along with this C2H6 will form. Yes, these will be minor products. their If the quantity is less, it will be made into a butt. If MCQs Let me ask you about halogenation of methane If chlorine is formed then you will say it will be formed.

[00:24:21]Halogenation of methane will form ethane. You You will say it will be made. Although this minor product Will be. There will be very little quantity but it will be made Correct. So what are you seeing here?

[00:24:29]Children? What are you looking at here? Here But you see that they are being consumed.

[00:24:34]Only. I am not becoming radical. then you will say that there is Net Decrease In the number of free radicals.

[00:24:53]Ok?

[00:24:54]This is the step, this is the step in which What is the number of free radicals? overall It starts to decrease, see you Are there any more radicals formed? Molecule. Correct Is? Did you understand this much? Mechanism Key The children understood the story in the initiation What happens? Ok? In chain propagation What happens? What happens at termination?

[00:25:14]Is? And many more things and I added it to it.

[00:25:18]have done. Now we want to talk to you about a few more things.

[00:25:19]want. That is the first thing that is Reactivity.

[00:25:25]Which halogen will be more reactive? Brother Fluorine will be the most reactive.

[00:25:29]After that there will be chlorine. then bromine and then there will be iodine. This has happened Reactivity. But Inside these labs Who is Feasible? What reactions will occur?

[00:25:47]There is one thing that we are studying theoretically.

[00:25:49]If it happens then it will happen. one would have been Actually, when you experiment You will go. When you go to experiment In the lab, which of these halogenations Is it feasible? So just keep it in mind Chlorination and bromination are feasible.

[00:26:04]Fluorination and iodination are feasible It doesn't happen. If you are asked about reactivity You should mark the order here. but if If you are asked who will give halogenation?

[00:26:16]So you would say it will give chlorine and bromine, Will not give iodine and fluorine. Why not Will you give? Because look, you have fluorine.

[00:26:24]Ok? You have fluorine. You can use it You will break it with sunlight. Ok? will break.

[00:26:28]Fluorine radical will be formed. Now this fluorine The radical of this is on the methane molecule Will attack. Hydrogen will be extracted from here And methyl free radical will be formed. Now this which There is a reaction, son, this one, this one This reaction is highly exothermic.

[00:26:43]Is. Not hexothermic, highly exothermic.

[00:26:46]There's a lot of energy coming out of here.

[00:26:48]Is. So handling it in the lab is really It is not feasible. So we say this that fluorine halogenation in practical Theoretically. So okay, we got it done.

[00:26:59]Executing it practically in the lab It is not possible. Your son is on the other side Iodine. Now you talk about this iodine. Now What will happen to iodine with methane?

[00:27:09]got the reaction done after which you will get HI and you will get it from here Meaning, one you will get CH3I and the other You will get HI which is similar to HCL mill was being found, HF was being found in the case of iodine HI Now this HI, son, is strong.

[00:27:27]is a reducing agent. What is? Strong is a reducing agent. What will he do now?

[00:27:33]will reduce it and this reaction You understand, right? Will reverse it. Now this A reversible reaction has occurred. here There can be no successful replacement. so I would say iodine also practically Halogenation will not give with methane. And Remember, off methane means start I told you I was successful Replacement of hydrogen atom with halogen Atom. So do this as a successful replacement.

[00:28:00]He can do it practically, but he cannot.

[00:28:03]I have told you the reason. I hope you You must have understood this much. So tell me brother You got the idea about halogenation of methane. all I told you what radical Is? What is the characteristic of a radical?

[00:28:14]Ok? What is Halogenation of Methane? What What happens in a step? Whether that initiation Yes, propagation, termination, a We have talked about reactivity. Whose?

[00:28:24]of halogens. Whose reaction was this, son?

[00:28:26]Halogen.

[00:28:29]Now let's talk about alkane also. Correct Is? Ok? Now let us talk about alkanes also.

[00:28:32]Let's take it. What is the reactivity of alkane?

[00:28:36]Ok? What about alkane? So remember to that the tertiary alkanes will be halogenation I will be more reactive as compared to Secondary as compared to primary. So here But the reactivity order of alkanes is also known as Discussed it. Tertiary alkanes are more Reactive towards halogenation as compared to Secondary as compared to primary. I hope This is the part of your mechanism All things about halogenation are clearly explained It must have happened. Now our next mechanism Yes son, it is nucleophilic Substitution reaction. I would like to be comforted So you absorb things, water and water Drink it. We will increase nucleophilic On substitution reactions. Is it right brother? P Are you feeling watery? Start it brother. A Nucleophilic Substitution Reaction What happens? See if you Talk about substitutions. This which Substitution is Same story here, isn't it with you?

[00:29:30]You have A and B. Ok? C comes and replaces one of these Gives. A and C are formed. Ok? and B He will go out from here. now like now You saw that in free radical substitution that radical was replaced by radical Was. Because it is nucleophilic So this means what is to come The group that is coming or the one that is coming Species is that must be a The nucleophile and what it will replace What would that be, son, some nucleophile?

[00:30:02]It will happen. But keep one thing in mind It is good that whenever we talk about alkyl halides of alkyl halide will be and nucleophilic substitution in it If we talk about children, then here this halogen this is also a nucleophile okay and If the incoming one is also a nucleophile, then both nucleophile children but But the nucleophile that replaces would have been the nucleophile that is being replaced We call it children's leaving group.

[00:30:37]What do you say? Leaving Group.

[00:30:44]Ok? Leaving Group.

[00:30:47]This is also a nucleophile, son. But Because he is taking leave, he is going away.

[00:30:51]So what shall we call it? We will call this Leaving Group. The Better Living Group It would be that easy for him to escape from the compound.

[00:30:58]will go and the substitution will be the same It will be done easily. Now this nucleophile What are they? What things are nucleophiles?

[00:31:05]What are electro files? I gave it to you In the MDCAT treasure video you have You must have seen it and if you haven't seen it then it is natural that Please check out the video. There I am I am giving you the treasure regarding this. Correct What is a nucleophile? Strong What is? What is a week? Ok? So he too You must check it out. so one nucleophile to another nucleophile to replace, to substitute Nucleophilic Substitution Reaction It is called. Now this is nucleophilic There are many types of substitution reactions.

[00:31:32]In which you get SN1. in which You get SN Two. in which your SNI comes near. in which you have SNAR It comes. Ok? There are many types of No? But what you want to discuss is this In the chapter, son is in intermediate.

[00:31:49]There are two of them inside your FSC, one is your You have SN1 and you have SN2. So I will cover this in detail one by one.

[00:31:57]I will tell you everything, so pay attention.

[00:32:01]Please consider it. Ok?

[00:32:04]Let's talk about children first.

[00:32:06]Bi-molecular nucleophilic of the substitution reaction. first one thing Keep in mind that bi-molecular substitution reaction that you have, right Is? by molecular substitution reaction What you have is what you have It's a single step reaction, son. Single Step Follows the mechanism. Ok?

[00:32:30]Ok?

[00:32:32]Through transition state.

[00:32:40]Acres Thru Single Step Acres in Single Step Through Transition state.

[00:32:49]Now look, there is a word called intermediate.

[00:32:53]And you have a transition state.

[00:32:55]Understand the difference in this when the transition state Let's talk about this actual product.

[00:33:00]It doesn't happen. Meaning in the transition state Whatever you see is an actual There is no product. Ok? first things first And what about here in the transition state?

[00:33:08]will be that Bond Formation Okay and Bond Dissociation will be a matter of that the bond would not be completely broken The bond will be fully formed. Meaning Bond that the formation or dissociation is Intermediate will be in the state. not completely It may not be broken or completely repaired. These Any product in the transition state actually It is not something you can achieve. This makes no sense Not an actual product. This is just one of your The transition state is where your reactant is turning into a product. between his The condition is. You cannot achieve this. This You cannot isolate. Ok? Whereas Intermediate products are those You can achieve it. Ok?

[00:34:00]Ok. So one thing is understood. Single Step There is a reaction. The transition state is formed here Is. Ok? Now the next thing we'll talk to you about is that this that primary alkyl halide.

[00:34:18]Ok? primary alkyl halide which Gives reaction. Ok?

[00:34:23]Nucleophilic vo by molecular Nucleophilic substitution mechanism Give through. This means that the primary The reaction which alkyl halide will give is by Molecular Nucleophilic Substitution will be. It will be a single step reaction. Ok?

[00:34:37]Now I will talk about the rest with the mechanism.

[00:34:39]Let me explain to you. Look, I have one here Alkyl halide.

[00:34:47]Ha, I take it out and make it.

[00:34:51]It is a primary alkyl halide. Isn't it Children? on the one fitted with halogen There is only one alkyl group. So its Meaning it is a primary alkyl halide. Ok?

[00:34:59]This is your primary alkyl halide. Correct?

[00:35:05]I am reacting to this from the nucleophile. with whom are you doing it Am? reacting with a nucleophile Am. When it reacts with a nucleophile If there is a reaction, children, what will happen?

[00:35:15]I am also explaining some things to you.

[00:35:17]Am. You will understand together that I Son, I have made it carbon.

[00:35:22]Ok? A bulky is mounted on carbon Alkyl group. Ok? It is mounted on One hydrogen, two hydrogen.

[00:35:32]And a halogen attached.

[00:35:36]This halogen, son, is above it.

[00:35:38]Partially minus and carbon electrophilic. mean charge on carbon It is partially plus. Ok?

[00:35:45]Now this is the nucleophile coming in.

[00:35:47]Kids, this nucleophile coming in Is, Ok? The nucleophile that comes in is What options does it have for this electrophile?

[00:35:58]To reach carbon? you here Let's see if it comes from here, okay? If will come from here So what will happen? Nucleophiles are halogens is also a nucleophile. what between them Will it happen son? There will be repulsion. What will happen?

[00:36:12]There will be repulsion. Because both of these are nucleophiles. Both are negative There are species. So there will be repulsion here. One So this is it. next thing one more thing Please understand that I am taking this carbon Karbonn's Zara Stereo I will also tell you about chemistry in writing.

[00:36:30]If you look at this carbon, okay? This You look at carbon. on this carbon An alkyl group is attached. you are watching yes. Two hydrogens are attached. Ok? And as well as on one valency of this carbon Meaning, halogen is also attached in one orbital.

[00:36:52]Here, let us assume that halogen is attached. Correct Is?

[00:36:56]Now the nucleophile that's coming in is that It can attack from where the halogen is present.

[00:37:01]Is it present? The answer is no. Because halogens Occupy this plane, this plane is the part of the orbital above the plane Who is already sitting in it, son?

[00:37:13]Halogen is sitting in it. So The nucleophile cannot go this way.

[00:37:16]Can. So the nucleophile is forced to deprotonate You will have to attack from the side. Because the forest is a step reaction. The halogen will come out No. in the presence of halogens The nucleophile has to attack. So this Because the nucleophile will attack oppositely Side. And from the opposite sides I wish I can say 180° that if there is halogen here then opposite the nucleophile exactly 180° What will have to be done to attack from the opposite side?

[00:37:43]We will have to do this, son, we call it rare.

[00:37:45]What is the back side called attack from rear back side Well, halogen can't attack from there.

[00:37:55]Where there is halogen, it is forced to be placed opposite We will have to attack from the side and when this happens so one The transition state will be created.

[00:38:06]Now remember the transition state I told you What did you tell me son? in the transition state We told you that becoming Bond and in a state of breakdown will be. where halogens and halogens and carbon The bond must be breaking.

[00:38:23]Ok? and nucleophile and carbon Bond must be forming.

[00:38:33]Correct. Correct.

[00:38:36]We call this condition beta transition.

[00:38:38]state. And why is it called a transition state?

[00:38:41]My children? Why is it called a transition state?

[00:38:42]Are? It's true that bonds are formed and broken.

[00:38:46]is in a condition of. that bond making and bond Both braking are happening simultaneously.

[00:38:52]That's right. Ok? Then what will happen is that The bond will be completely broken and the carbon and the bond of the nucleophile is completely But it will be made. Then you will see that R on carbon is like that. H is like that. Correct Is? and here comes the nucleophile and Your Halide as a Living will come out Group. Ok? As a Replacing Replaced Nucleophile. Did you understand this much? This If you look at the entire step, here What is happening son? What is happening? Some?

[00:39:27]I've told you things that single There is a step. Ok? single step along with I told you one more thing. What?

[00:39:34]The mechanism of primary alkyl halide It will be SN2. Ok? Two Step There will be a reaction. Sorry single step reaction will be through transition state. Now some things I'm adding more here. what is that Nucleophile Attacks From Rare back side of halide Leaves from where the halide will leave from here The halide will come out from its opposite side.

[00:40:05]Which nucleophile will have to attack?

[00:40:07]It's okay, which you can also call 180° opposite.

[00:40:10]You can, okay, next thing is bond making.

[00:40:18]Bond making whom during son Bond Making of which carbon and Nucleophile. Ok? End Bond Breaking and Rupture of Bonds Carbon and whose bond brother? of halogens.

[00:40:32]Akers simultaneously This will happen together.

[00:40:41]And what will we do with the situation in which this happens?

[00:40:43]What are you saying son? calling it a transition state Are. Did you understand this much? I understand this much Went? Ok.

[00:40:51]You understood this. Ok?

[00:40:54]Why would the attack be from the rear back side?

[00:40:57]Why will it be 180° from the opposite side? Ok?

[00:40:59]and bond formation and bond breaking, which is That is what you call a transition state.

[00:41:03]Let me talk to you about some more things. A few more things We do.

[00:41:08]Hybridization Whose? of carbon. Ok? Hybridization of carbon. I will remove it for now.

[00:41:25]Hybridization of Carbon How will the change happen son? will be in the start sp3 is ok? So sp3 There will be change from sp3. of this carbon Hybridization occurs due to beta transition SP2 in the state and again what happened son?

[00:41:43]sp3 So what happens in the transition state?

[00:41:46]Is it hybridization brother? is sp2.

[00:41:49]What was it before? sp3 and later Will it happen? sp3 Keep this in mind too Please keep it. Ok? I understand this much for now Went. Now which way do we go? stereo Towards chemistry.

[00:42:08]Let's move on to stereochemistry. If If you look at its stereo chemistry, you Saw that there was carbon. RH H on carbon and its But a halogen was present. There was a Halogen. Halogen is made here. Correct Is? Halogen. incoming nucleophile nucleophiles having forced to because halogen is still there, it turned out If not, then attack from the opposite side.

[00:42:34]Ok? Now just look.

[00:42:39]Now just look.

[00:42:44]Ok? That halogen was installed here.

[00:42:49]Halogen used to be here once upon a time. Now So, the nucleophile has arrived, right?

[00:42:53]Near. Ok? This is the nucleophile Looks like it's on the opposite side. Correct? So when Bhi kabhi aisa ho ke ek group tha aav di Plane but the incoming group laga billo di Plane. The opposite became the opposite. So we make it It is called son inversion. What do you say?

[00:43:12]inversion of configuration The product that will be formed after SN2 That will be the inverted product you have. How?

[00:43:24]Will it be inverted? that if the halogen above di was plain so now the nucleophile is Above the plane is not present, below the plane is present will be. Ok? We call this inversion.

[00:43:32]Off configuration and remember here There is 100% inversion. What happens? This Also called wall inversion. You must have heard the name You. Wadden Inversion.

[00:43:45]100% what will happen here son? Inversion.

[00:43:48]and if the halogen is the nucleophile It would seem to happen where it would not. It seems so Then we call it retention. So here There will be no retention at all. what here Will it happen son? There will be 100% inversion. This talk We did it stereochemically. stereo What is its chemistry? We saw that.

[00:44:03]Now I will talk about it of kinetics.

[00:44:11]See, Kinetics is what we are, son.

[00:44:13]Let's take it out with slow steps. and slow step What do we say to the son? RDS. RDS Meaning rate determining step. what do you say Are? Rate Determining Step. Correct. Here But because there is only one step, kids. Just like that Isn't it? There is only one step. what is this step will be? Slow step. And in slow step you Look how many molecules you can see?

[00:44:32]Two. How many molecules are visible? Two.

[00:44:34]That is why when we write the rate, the rate of What is the reaction, children? you had read Under the rate law, the rate of reaction is Directly proportional to the product of Molar concentration of reactants. One You have the reactant. Good molars Concentration of reactants. as many as Be the reactant. One reactant is your Pass RCH2X your alkyl halide. Ok?

[00:44:55]And who is the other one, son? Nucleophile.

[00:44:58]Well, instead of this you can also write substrate.

[00:45:00]You can. So substrate means substitute Has been. So you can write it like this also.

[00:45:06]Rate equal to k constant arrived. His After that you can write substrate and nucleophile.

[00:45:15]Correct. Now here if I talk about order If I do this, what will be the order, son? Order you You know this is experimental value.

[00:45:22]Ok? But yes, if you rate law you are given So you can tell that power one power 1 1 + 1 How much will this second order be?

[00:45:30][sound of clearing throat] Ok? If I talk about molecularity So how many molecules are participating?

[00:45:34]Are?

[00:45:37]Molecules are also participating two.

[00:45:39]So what will be its molecularity here?

[00:45:41]But? Two. We have talked about kinetics.

[00:45:43]I have talked about kinetics. Now we talk are its thermochemistry.

[00:45:52]Thermochemistry and Solvents.

[00:45:56]And what kind of solvent should be used. Ok?

[00:46:01]If I talk about thermochemistry, son So it is exothermic.

[00:46:08]Ok? This is why favored by Favored by low temperatures or decreases You can also write the temperature.

[00:46:19]Because it is exothermic. Ok?

[00:46:20]Exothermic reactions are favored when You lower the temperature. Ok? These The matter is settled. The next thing we do is son of solvent.

[00:46:30]Remember that SN reactions occur, SN Reactions are, they are favored by they are Favorited By Polar solvent.

[00:46:45]Polar solvent. Ok? that polar solvent SN favors the reaction. But here Son, we are talking about SN2, not SN.

[00:46:54]It is happening. Now there are two types of polar solvents.

[00:46:57]There are children. One is called a protic having protons such as H2O polar protic Solvent H2O is called a polar solvent.

[00:47:06]aprotic solvent polar a protic Solvent such as your acetone that it is polar but not a proton It is also polar and also has protons meaning H There is also a plus. So SN2 reactions are favored Bye Favored by Polar Aprotic solvent.

[00:47:31]Ionization is not required here.

[00:47:33]Ok? Ionization is not required Here. So did you understand this much? here I have covered everything. Ok?

[00:47:40]that bimolecular nucleophilic Will there be a substitution? Ok? here How to write a mechanism? Nucleophile Why would he attack from the back side? transition What is a state? What is hybridization?

[00:47:52]Will there be any change? what is stereo chemistry She says? What is Kinetics?

[00:47:56]What is thermochemistry? and solvent kiss What kind will we use? Did you understand this much?

[00:48:00]Now towards which side do we move son?

[00:48:02]of unimolecular substitution reaction On the side. Whose side? Unilateral Substitution On the reaction side. Now unimolecular good One more thing Rather, I will add it here.

[00:48:14]unimolecular substitution reaction which Son, these are akers in Single Step.

[00:48:27]Sorry in one step Sorry sorry sorry Akers in two steps.

[00:48:37]It takes two steps here. Ok? and two more Why do steps occur? because you know Here is the tertiary alkyl halide Participates. Who Participates Does it? Tertiary Alkyl Halide.

[00:48:50]Tertiary alkyl halide whenever Nucleophilic Substitution Reaction If we give it, we will give through SN one reaction.

[00:48:56]Why? Why? Because the tertiary ones are No son, tertiary carbocation which is tertiary carbocation which is You know he is stable. What does it mean will form. Ok? There will be a form. So first step will have a tertiary carbocation form and then In the second step, this carbocation The reaction will take place with a nucleophile. Ok?

[00:49:16]So this reaction takes place in two different steps.

[00:49:18]will be.

[00:49:20]Now if you pay attention, there are two steps.

[00:49:23]We will discuss each step one by one.

[00:49:25]and all the important things that I will keep telling you that. as I always say what is the first step?

[00:49:32]Is? The first step is step number one.

[00:49:35]What did I say? Step number one.

[00:49:38]What will happen in step number one, son?

[00:49:39]Formation of Formation of Tertiary Carbohydrazine. You have to take tertiary alkyl Halide. Is it a tertiary alkyl halide?

[00:49:47]Children? Please tell me.

[00:49:50]Is it a tertiary alkyl halide? So you You will say yes yes yes yes sir this is tertiary It is an alkyl halide. So in the first step What will happen son?

[00:50:00]What will happen in the first step? Ionization Will happen. Ok? What will happen in the first step?

[00:50:05]Ionization will occur. What happens after ionization?

[00:50:07]Will you get it son? You will get a tertiary Carbohydrazine.

[00:50:11]What will be getting? A tertiary carbocation. And Halogen as a nucleophile from here on out It will come out. So be it. seconds after that What will happen in the step, children?

[00:50:24]Ok? What will happen in the second step? This which A tertiary carbocation is formed Ok? The tertiary carbocation that is formed is will interact with the nucleophile and What will he make for you? Making you this will give a bond between carbon and nucleophile.

[00:50:42]Bond between carbon and nucleophile. these two There will be reactions in steps.

[00:50:48]That's right. It is exactly like that. But But pay attention to a few things.

[00:50:53]Inside Chemistry.

[00:50:58]Are you understanding the matter well, children? good I am getting the point from this. Are you enjoying it? Correct Is? I hope you are enjoying it. stereo If I look at chemistry, I have this It is a tertiary alkyl halide.

[00:51:11]Carbon. orbital of carbon Halogen. tertiary is fine but Carbocation of tertiary alkyl halide Because it is stabilized, that is why What will happen to children's carbohydrates because of this?

[00:51:28]cation will be formed, okay, carbocation will be formed that Halogen will come out from here as a Halide ions Okay, it came out, which means that Now this carbotine, this carbotine It is good that its hybridization is also the same.

[00:51:45]There will be a change, son, here I am Let me also tell you about hybridization. first is sp3 has just become sp2 and what is the after reaction Will it happen son? The return will be sp3. Correct Is? So right now hybridization is here What happened to its sp2 and its orbital?

[00:51:59]Both the above plane and the below plane are empty.

[00:52:01]Ok? Now the second step was yours.

[00:52:03]Step number one. Now this is the second step.

[00:52:06]near you.

[00:52:08]Ok? This is the second step, son.

[00:52:10]the path in which the nucleophile will react With carbocation. Now for the nucleophile Son, you have both chances. both chances Yes brother. This is above the plane because halogen It was there, now it is not there. The halogen is gone. halogen Went. Ok? Tata is gone bye-bye. Ok?

[00:52:27]He can attack from here also. What does it mean There are two possibilities here. Two possible You will get the products. one in which one in which The nucleophile must be placed above the plane.

[00:52:42]Where there used to be halogen. and one more The product can become the one in which the coming The nucleophile is below the plane.

[00:52:51]Go. Both possibilities are available here. Where But it was halogen. Where was the halogen, brother? Here Was.

[00:52:59]I am making this dotted line. What does it mean It is not there. Was here.

[00:53:05]There was halogen here. Ok? where at There was halogen, now the halogen is gone, so that place It became empty. So the one who is coming The nucleophile is there, son, which is going to come Nucleophile is also above the plane and if above the plane is applied then the same It was installed in the place where halogen was. This I would call the product brother retention.

[00:53:23]And if it hits the opposite side, what should I do about it?

[00:53:26]Will I say? Inversion.

[00:53:29]So, one thing I understood is that here both Things are possible. Ok? SN1 Reaction Both things are possible. here There will also be retention. Why would it happen? I understand the matter Isn't it happening? Ok? And here the inversion Will also happen. Both will be here in time. Correct Is? You are understanding it well, aren't you?

[00:53:48]Retention inversion here why both Will it happen? Because the halogen is gone. above the plane is also empty, below the plane is also empty.

[00:53:52]Both. Now if you look at these two, Both are mirror images of each other. If If I place a mirror in the middle, you will see this They look like mirror images of each other.

[00:54:02]Have been. And so you have isomers which are Mirror images of each other but on top of each other Do not superimpose. Let's suppose these carbon That was chiral carbon. So optical or Your active compound will also be formed. Ok? So These compounds here are related to each other are mirror images. These are compound one and compound The two are mirror images of each other. But one Cannot be superimposed on another. Its Meaning this compound and this compound are related to each other.

[00:54:28]What are they? Enantiomers.

[00:54:32]What are they to each other? These are each other's are enantiomers. Isn't it? This is what happens, right?

[00:54:36]Enantiomers that are mirror images of each other but Non-superimpossible. So mirrors of each other There are images. 50% will form this enantiomer Son, this one will be made 50% more. Because both There are chances of both above and below. so one Such a mixture my children A mixture containing 50% of two Be of enantiomer. Meaning equi molecular.

[00:55:01]What will be built here? Equ will be made here molecular Equ Molecular Mixture of Two Enantiomers I am remembering something I remember that if you have two enantiomers Yes, and both are in equal numbers.

[00:55:26]If the molecule is present in 50-50% then such mixture what do we call racemic racemic Mixture. This means racemic reaction inside SN1 It will be a mixture. This means I can say that I believe that racemization occurs inside SN1.

[00:55:43]What happens? Racemization.

[00:55:46]So if you are asked where is the racialization?

[00:55:48]it occurs? So you tell me. occurs in SN1 Is. Does not occur in SN2. All these things came Hope you have understood. Now we will move forward.

[00:56:01]Thermo Chemistry and solvent What does thermochemistry say, son? This too It will be exothermic overall. Ok?

[00:56:16]It will be exothermic. How to use solvent Is your son here? Here you have solvent Polar but protic solvent has to be used.

[00:56:25]Polar protic solvent.

[00:56:27]Like water.

[00:56:30]Ok? Like water. Now the question is that Why are you using water? Because Look, understand the matter.

[00:56:37]This halogen that had gone out is also returning.

[00:56:39]So this carbocation can react, right?

[00:56:41]From. Isn't it? So water comes and plays a little prank Will do. Water will say, hey brother, why? Halogen You left, why react again?

[00:56:50]You have. So what will Water do? This which Halogen is formed, not halide ion which is formed inside the water because it has protons the proton will start to surround it okay this Like these are partially plus science You know, this is how the water molecule cage looks like.

[00:57:06]He will lock me up in a kind of cage What will the water molecule do to itself?

[00:57:11]with the help of protons okay these protons of your What will the water molecule do with the help of He will capture this helide Will not allow any reaction again. So a job So here it is brother. One thing came up that Your water which you have polar protic The solvent that has been taken is its protons.

[00:57:32]Who will we catch and hold?

[00:57:34]ion of the halide due to which it is again Cannot react. One thing is this Went. The second thing is that if you use water If you are pregnant then this also helps in ionization.

[00:57:44]Will do. What will he do? Even in ionization It will help if you have used water.

[00:57:48]No son, if you use water here then water Because what would be the dielectric constant Is? The dielectric constant of water is It is around 80. Ok? of water What is dielectric constant? 80's It happens around. This means that carbon and The polar bond of halogen is polar Water will reduce the bond by 80 times. whose What will cause ionization? Easy.

[00:58:07]Firstly, it also helped in ionization. Above released from the atmosphere with the help of its protons I even turned off the halogen, caged it, surrounded it so that he could play with it again cannot interact with that tendency so that The nucleophile comes and takes place in the reaction With whom to do it? With carbon.

[00:58:29]I hope you also like this solvent story.

[00:58:31]You must have understood that polar A proteic here Why ah we are. Ok? come now Let's go son to Kinetics.

[00:58:38]on kinetics what kinetics says Is? Kinetics says the rate is Directly proportional to the molar Concentration of reactants. Now the reactant which Hey son, where will you get it from? Slow Step Will you take it out or fast? You will say Sir Slow Will remove it step by step. So in slow steps you Look how many molecules there are, son. just one It is a molecule and that too of alkyl halide. So I would say substrate. to alkyl halides What am I saying substrate? Because Substitution is taking place in it. So what am I Shall I write, son? Rate equal to K and only and Just your alkyl halide meaning substrate Because in slow step there is only one Reaction is the reactant. nucleophile then Came in the fast one. We take slow steps Take it out. Ok? Now if you are here Pay attention, what will be the order, son? rate If you write order by expression then order What will happen? First. and molecularity What will be made?

[00:59:27]What will molecularity become here? How many?

[00:59:29]Molecules participating?

[00:59:30]You too should do molecularity. will you say Because how many participants are there in total molecule?

[00:59:34]Are you doing it? Two. molecularity is what And what are the orders from each other Children? things were slightly different from each other Are. So, the order here will be first. Ok?

[00:59:44]Did you understand this much? So much about you I understood. Now you know what SN1 is.

[00:59:49]Son? What is SN2? All that is possible There is information, the things that are possible, I have told you here. I hope You must have understood these many things. Now which Next is our mechanism, son, his name is electrophilic substitution reaction of benzene that benzene is electrophilic How does a substitution reaction work?

[01:00:13]So let's start with electrophilic Let's go to the substitution reaction, a good one.

[01:00:19]I will say again what I I have already told you this many times What is substitution Removal of one group from another The removal of an atom or a group of atoms and its Someone else coming here instead It is electrophilic substitution. Its Meaning one electrophile is used for the other will replace the electrophile. if you Talk about benzene, children.

[01:00:37]Passes that would have allowed sides to make substitutions Yes, they are all equivalent. means this that this benzene that you have In this every corner is equivalent. Meaning You will not find any unique product. You You can substitute this hydrogen.

[01:00:56]Do it, do it. Do it. means any You will substitute hydrogen.

[01:01:02]The product will not be unique. every time you You will get the same product. So if someone tells you How many sides are there for substitution?

[01:01:10]There is only one for me. Because every time you have someone Unique product will not be available. Ok? So That's why instead of all of these, I'm going to just pick one.

[01:01:17]I am making it.

[01:01:20]Ok? And its reaction is an electro I am getting it done with the file. If I do that If I do it son, what will happen? that this electrophile which is this electrophile will replace And will take his place.

[01:01:43]H+ will come out. Ok? So this is what The process is completed in which an electrophile will replace the other electrophile.

[01:01:50]What should I call this? electrophilic Substitution reaction. This which Electrophilic substitution reaction is Children, those benzenes occur in several steps.

[01:01:59]The first step of which is Beta Formation of Electrophile Because so many questions arise from its mechanism.

[01:02:10]If you are not asked, I condense a little.

[01:02:12]And I have started teaching you. Ok?

[01:02:13]Formation of electrophile in the first step It happens. How would your reagent be Yes, let's suppose your reagent is A This is one of your reagents. this interact With whom will he do it? With Catalyst.

[01:02:32]The catalyst and reagents will combine and will what? You will get Catalyst And let's suppose this B got added. And this A This will become an electrophile. Ok?

[01:02:46]Then what will happen in the second step, children?

[01:02:50]What will happen in the second step? Formation of Carbohydrazine.

[01:02:54]Formation of carbocation. of carbocation You know about hybridization, right? sp2 is Is. Ok? Formation of carbocation which is Also called arenium ion. Why Erinium What do you say, son? Because aromatic carbohydrates A cation is formed, isn't it? That's Why Erinium This is called this. what happens is that benzene Which is, benzene is what you have, right? One I am demonstrating the creation of hydrogen here.

[01:03:18]But. his and what your electrophile is Will interact with each other. Let's suppose this The electrophile was yours. Ok? With this There will be interaction and what will he do? This double This bond will seek the electrophile.

[01:03:32]Because the double bond is an electrophile There is a Seeking Bond. Ok? after which What will happen?

[01:03:41]What will happen after that? that this hydrogen This electrophile will also be added. These The bonds will remain the same. that this bond Whatever it is will break down and on this carbon There will be positive charge and carbocation There will be formation. Remember that benzene never Also, regarding aromaticity, this pi bond There is a system, there is no bargaining about it.

[01:04:01]Does. So what will he do? retain again Would like to do it in step three. what we call Yes, son, loss of proton. what do you say this we? Loss of protons.

[01:04:11]Now what is this loss of proton?

[01:04:13]Does it happen children? That this is H and this is E There is competition between Bond that electrophile would win goes. Ok? And this bond is This is the product of hydrogen and carbon.

[01:04:26]It will shift in the meantime. after which This double bond should be formed again.

[01:04:33]Will go. Restores aromatic system Will go. The electrophile will remain attached and this Hydrogen edge is a positively charged edge The proton will come out. That is why this step We call it loss of proton. Now Loss of The next step after protonation is Son, your step number four and last step In which the catalyst is recovered. What it occurs? Recovery of Catalyst.

[01:05:00]What happens in recovery of catalyst is that The catalyst that was combined with your With this B, okay? That and these protons Will interact with each other. proton which is will take this B out and HB someone The compound may become another catalyst Your catalyst will get freedom It will recover. I understood this much. Correct Is? So the mechanism is electrophilic Substitution of benzene has all these The steps come. What do you remember now?

[01:05:28]Is? You have to remember which reaction Happened?

[01:05:35]What reagent was used in that reaction?

[01:05:39]Ok? Which electrophile produces Happened?

[01:05:45]Ok? And remember the product too, so what?

[01:05:47]That is a good thing. Like the first reaction Your halogenation.

[01:05:55]The reagent used in halogenation, son, is Who will it be? That would be halogen. x2 x2 Let's write. Halogen. electrophile will form Halonium ions. What shall we call this?

[01:06:06]Halonium.

[01:06:09]Ok? And what will the product be?

[01:06:11]That will become hello benzene. What will happen? Hello!

[01:06:14]Benzene. This is Hello Benzene. Chlorine was So chlorobenzene will be formed. If bromine was Bromobenzene will be formed. Ok? Hello!

[01:06:21]Benzene. Similarly, Friedel Craft Alkylation.

[01:06:27]Friedel Craft Alkylation In which you react with alkyl halide You will get it done. electrophile will form Alkylamine.

[01:06:38]Alkylamine Could be methyl, could be ethyl, May contain propyl, may contain isopropyl It could be anyone. and which The product you will get will be alkyl Benzene. What will happen? Alkyl benzene.

[01:06:53]Ok? Methyl benzene, Ethyl benzene, propyl benzene, isopropyl benzene, some Too. After that you remembered the third mechanism The one to keep is Friedel Craft. Understand Will you be there? Acylation Ok What will you do in that, son?

[01:07:12]React with acyl halide and The electrophile you will get from here Which will be the acylium ion?

[01:07:20]Asylum Ain is ok Asylum Ain After which you will get ketones what will you get call it acyl benzene or Then you say you will get aromatic ketone.

[01:07:36]Ok? The fourth mechanism you should remember That is nitration.

[01:07:42]Well, I forgot one thing.

[01:07:44]Catalyst. I will write it together with Catalyst I have been. Ok? writing in brackets Am. Lewis acid will be used here Lewis Acid. And what could that Lewis acid be?

[01:07:52]Son? It can be AlCl3 if chlorine You are getting the reaction done. Ok? Or Then it could also be FeCl3. Remember this thing Please keep it. Ok? I did not add Catalyst I said sorry. But I will write it here.

[01:08:03]Lewis acid will be used as catalyst Here I will write rather reagents Slash Catalyst Okay, so here I go.

[01:08:17]What will be the use here too, son? Lewis Acid where should I write Lewis acid understand Who is being talked about? AlCl3 or FeCl3 It is being talked about. Ok? After that you Is nitration okay? Nitration is to be remembered.

[01:08:30]The reagent used in nitration is HNO3.

[01:08:35]And the catalyst that will be used with it will be H2SO4. Write the catalyst in brackets.

[01:08:39]I have been. Ok? from here which Electrophile will produce children that will be NO2+ which we call nitronium ion Are.

[01:08:48]And the product that will be made by my children Nitrobenzene will be formed. What will happen?

[01:08:53]Nitrobenzene. Ok?

[01:08:55]The last mechanism you will remember is Sulfonation.

[01:09:00]In sulfonation you will use fuming Sulphuric acid. What will you use?

[01:09:04]Fuming sulfuric sulfuric acid.

[01:09:10]This is the reagent as well as the catalyst.

[01:09:13]Fuming sulfuric acid by another name They call out. also oleum pyrosulfuric acid They say. Ok? The formula is H2S2O7.

[01:09:21]Ok? You will react with it The electrophile is SO3 and you You will get benzene sulfonic acid. This is Nitrobenzene.

[01:09:30]This is nitrobenzene and this is benzene Sulfonic acid. benzene sulfonic Acid.

[01:09:44]Ok? You will get all these things from these mechanisms.

[01:09:47]Have to remember from. I hope it's no difficult task It is not for you. that it is better than Mashallah All of you are children. So it's no problem for you It is not a job to remember these things.

[01:09:58]So remember this and leave me a comment.

[01:10:02]I will tell you how you liked today's class.

[01:10:04]It started. In which we have discussed all the mechanisms Discussed which MDCAT Chemistry I need you. Ok? And if you If you liked today's class, please let me know in the comments.

[01:10:18]Do let me know how you liked today's class.

[01:10:21]It started. did I miss any details Is. We'll talk about it in the comments.

[01:10:25]And if you liked today's class then Please like the video so that it can be seen in the next Let me bring the session quickly. I I keep the same target for this video as well.

[01:10:35]If you liked the previous one 500 times If you have given it, I will bring the next session soon.

[01:10:41]And in the next session I will do the same in the group I will put a pole in which I You tell me what you will be talking about in the next class.

[01:10:49]I want to. I hope as many things as possible today I have taught you, I have taught you, I understand, you enjoyed today's class.

[01:10:56]You have done Chemistry and now you need Chemistry.

[01:10:59]The mechanism may not seem that difficult to you.

[01:11:01]How much are you getting before today's session?

[01:11:03]Used to apply it. [nasal sound] Thank you so much kids. Thank you so much. And Now we will meet in the next session. Video Likes Please like, share and like with your friends Let me know in the comments whether you enjoyed it or not.

[01:11:16]Allah Hafiz.