 they should write down nomenclature of alkene. See in the nomenclature we have we have to follow the rules ok there is 2, 3 rules 3, 4 common rules we have which is not true for all kinds of compounds. Sir between alkene and alkene which is most that we cannot say. So what see we cannot compare this way it's like see what we didn't you and you who is more powerful say something like that ok. So it's but you can say here it's possible but 2 compounds if you see 2 compounds you are comparing right one is unsaturated compound and other one is unsaturated compound. Double bond formula we use when we have RS of same structure these 2 are completely different one is alkene other one is alkyne these 2 are completely different right. So we cannot compare the stability here but if carbon-carbon bond has double bond characteristics the bond strength will be what more. So if you can say this thing if this molecule we have ethane and ethene what we can say we can say these which one of these 2 carbon-carbon bond is stronger that we can say overall molecule we cannot compare right. Obviously this is double bond this one is stronger than this the bond length ok. So that double bond all those structure or the rules that we use we use only for what only for RS of same molecule ok. 2 different molecule RS we cannot compare by those 8 or 9 rule that we have discussed in stability of various resonating structure right right. Nomenclature of alkanes like I said we have to follow the rules into this what is the rule number 1 right or nomenclature of alkanes they mainly will see questions into this with questions only you will understand the rule directly if you go through the rules you won't understand like how do you know solve the questions and look at the important things which is there or not right. So first rule to write down the first rule is select the longest carbon chain select the longest carbon chain this is known as the parent chain principal carbon chain or parent chain. Second rule number 2. Sir all these rules are in order we have to do it in order. Yes rule number 2 if the 2 carbon chain in a compound if the 2 carbon chain in a compound have equal number of carbon atoms then the carbon chain which has more number of locates locates or substituents then the carbon chain which has more number of substituents is the parent chain. This is example you see 1 2 3 4 5 6 7 which one is the parent chain. See if you go this way 1 2 3 4 5 6 7 right 1 2 3 4 5 6 7 so 2 carbon chain has equal number of carbon atoms right so if you select this as the parent chain then what happens it has only one substituents right substituents the branch that is that is present in the parent chain. So this chain has only one substituents but if you select this one as the parent chain this one is the parent chain so this has 3 substituents one is this another one is this and another one. So this is the correct no select parent chain. Now when you select the parent chain you have to number the carbon atom numbering should be done after this and numbering means what we can start the numbering either from this side or this side 1 2 3 4 5 6 7. So this numbering should be done in such a way so that the locates or substituents gets least possible number that is rule number 3 the next rule to write down. So what if you have two chains that are the same length and that is the same number of branch chains. Then you will see the sum of locates we will discuss that this example we will discuss. Write down rule number 3 numbering should be done numbering should be done in such a way numbering should be done in such a way so that the substituents gets least possible number least possible number least possible number this is known as lowest set of locates rule lowest set of locates rule. Next line if the carbon chain contains more than one substituents the carbon chain contains more than one substituents then the sum of locates should be minimum. Next rule all the substituents must be written in alphabetical sequence. Suppose we have this example 1 2 3 4 5 6 and here one carbon atom is present. So if you have let us say you look at the branches both the branches are equal length and equal number of substituents. I will come to that we will see sum of locates we will see examples. Have patience half an hour of course it will take you to the examples you will understand. So this is the compound here so obviously the longest chain is what? Longest chain is this one. Now we can start numbering from this side of this side two possibility we have. If you start from this side the numbering will be 1 2 3 4 5 and 6. So the position of this locate is third position. If you start from the other side 1 2 3 4 5 and 6. Since this numbering gives the least possible number to this carbon atom which has the locates that is why the correct numbering will be this one this is wrong. What is the name of this compound? 3 methyl hexane. This one you see 1 2 3 4 5 6. Here we have 1 carbon and here we have 2 mon. If there is another carbon attached to the other one. If you change the molecule then things will be different right. So now go look at what I am saying. If you attach No to number 4. Number 4 here. We can choose it from any side. You are seeing one carbon atom here. Yeah. Then it will be about the very side. So we can do anything. See in this case we will see that is what I am taking this example. I will do this and I will come back to this. So in this one we have to start numbering from this side any confusion. If you start from this side then 1 2 3 4 5 6. And you see we have 2 substituents present. So this side if you do the numbering then the sum is what? Sum is 5 2 plus 3 is 5. This side if you do the sum is what? 5 plus 4 is 9. So we will follow the lowest sum of logins. This 2 gives 5. This 2 gives 9. So this one is wrong. This one is right. Okay. So if we have more than 1 substituents then we will follow the lowest sum of logins rule. When we have only one substituents present then we will give the least possible number lowest set of logins rule. Now if you attach one carbon here then 3 and 4 and 3 and 4. Any way if you do you will get the same answer. Understood? This one you see. 1 2 3 4. Here I attach bromine to D. 1 2 3 4. Bromine this one. What is the correct numbering? 1 2 3 4. 1 2 3 4. Right? If you start from this side then the position will be 3rd and 4th. Here it is first and second. So lowest sum of logins rule. If you start from this side 1 2 3 4. If you start from this side 1 2 3 4. Which one is correct in this one? In this one you see the difference is what? 1 2 3 4. Here you see the sum of logins in both numbering is different. This side you are getting 3. Here it is 3 and here it is 7. So we will follow the lowest sum of logins rule. The correct numbering is this one. This is wrong. Now in this one the sum of logins are same. 2 plus 3 is 5, 2 plus 3 is 5. Now in this case we will get the least possible number to the substituents which comes alphabetically first. That is bromine. Bromo. It is clodo. So the correct one is this one. This is wrong. Also will be 2 bromo, 3 clodo butane. Is it clear? Is it clear? These 3-4 rules are clear. So this is the rule. It is common for all the compounds whether it is alkene, alkene or any functional group is present. Only few things you have to keep in mind that where we should give the more priority to which of the functional group. But these 3-4 rules that we have discussed it is common for all the compounds. Now I will give you some example. Write down the name of these compounds. The first one is. You can write down the name of these compounds. The first one. The first one is the first one. The correct one is 2, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, Sir, do you take tetrahedra as an algebraic? No, I want to know. Diatry tetrahedra will take in alphabetical sequence if the complex, if the substituent is complex, in case of complex substituent, for simple substituents you want to take. What is complex substituent? Sir, which case do I take in alphabetical sequence? So, the ethyl and the clodo will have a rank first. Sir, for the fourth one, can we write 2 comma 2 comma 2? No, longest chain first to select. Oh, the choice. Here if you remember from this one, then we have 2 to time details. And this one will be fourth time. Third, if you do 1 to time 2 clodo and 3 to time detail, sum of tokens, if you do 1 to time detail, that's why we follow this. Sir, 10. No, no. Just you have to follow the rules. Sir, wasn't it the 7? 7 is 10. Question. That's question. X, X, R, R, X. Sir, it's 7. 7 is 10. 1, space, that. What is the importance of this? Okay, I see. The first one. The numbers are selected by form. The numbers are selected by time. And there should be no space. No space. That's the longest chain is what? 1, 2 and 3, right? Sir, name of the silly word? 2. 2, 2, time ethyl propane. Okay, I listen to one thing. That these numbers are separated by comma always. Okay, you cannot write down dash here. Numbers and letters are separated by dash. And there should be no space in between. Okay, if you do not follow this, you'll get 0 marks in the exam. Okay, however you do. Time ethyl is propane or time ethyl? No, there's no space. Okay, so 2, 2, time ethyl propane. The longest chain is what? 1, 2, 3, 4 and 5. So what we can write? 3, 3 and third question we have ethyl propane. 1 and 2 carbon, right? So it's ethyl. 1 and 2 carbon, ethyl. 3, 3, ethyl pentane. For this one, the longest chain is 1, 2, 3, 4. So 2, 3, time ethyl, ethyl. For this one, the longest chain is 1, 2, 3 and 4. You can number the carbon atom from this side. If you number it from this side, you'll see 1, 2, 3 and 4, right? So in this side, the sum of locates is what? 2 plus 3 plus 3. Because we have third question, we have 2 ethyl groups, so 3 plus 3. That is 8. If you count from this side, so 2 plus 2 plus 3, that will be 7. The correct one will be what? The correct one will be the white. This is not correct. Right? So name is what? At second position, we have methyl. And 3, we have chloro. So first we'll write chloro in our vertical sequence, right? So 3 chloro. 3 chloro. 2, 2, time ethyl. You take. Green. She'll go in the order of this. What? Appropriate. She won't get emotional. She won't get emotional. Okay. What do we usually take the functional group? The functional group is there, then we'll discuss that also. Sir, CL is not functional group. CL is a functional group. CL is a functional group. But we'll follow the sum of locates rule here. It is not that the parity of CL is very low. It comes down very low. It has lesser parity than alkene or alkyne. We'll discuss that later, functional group. Okay. Now, this one, the longest one is... We'll start from this side, right? 1, 2, 3, 4 and 5. What is the name? 2-methyl pentene. For this, it is 1, 2, 3, 4 and 5. What is the name? Sir, you get 6, sir. 1, 2, 3, 4, 5, 6. Where? Sir, you get 6, sir. Okay. Sir, you get 6, sir. Sir, from this side, right? 1, 2, 3, 4, 5, 6. 3, 3 times 6, sir. Sir, how do you get 4, 5? 3, 3 times 6, sir. What about this one? 1, 2, 3, 4, 5, 6. 3, 4, 5, 6. Ethyl first and then methyl, right? It is 3, 4. 3, 4, diethyl. Okay. One note you write down here. Di, tri, tetra are not considered in alphabetical sequence. Are not considered in alphabetical sequence. Di, tri, tetra are not considered in alphabetical sequence. Wait, wait, wait. Not considered in alphabetical sequence. If, if the substituents is not complex. Sir, let's select for the third one. 2, 3, di-methyl butane. Why is it wrong to write 2, 3, methyl butane? 2, 3, methyl butane. Because if you put di-methyl, only when the same card would have to be 2. See, 2, 3 when you write, it means 2 methyl group are present. Right? So, for 2 methyl group, you have to write down di-methyl. Right? See, what can I say? If you say that why not 2, 3, methyl? Because you have 2 methyl groups, you have to mention in the name that there are 2 methyl group present. But you can also say, sir, 2, 3, if you write, it means there are 2 methyl group present on 2nd and 3rd card. But we take this di-tri, tetra-methyl. It actually signifies the number of methyl group present in the molecule. So, 2, 3, methyl you cannot write. 2, 3, di-methyl you have to write. So, 2, 3, methyl you cannot write. 2, 3, di-methyl you have to write. 2 methyl are each of them. Then how do you write? 2 methyl are on each of them. Yeah. When we write like this 2, 2. 2, 2, di-methyl. 2, 2, di-methyl. 2, 2, di-methyl. That's one. Yeah. 2, 2, di-methyl. Yeah. This one? Yeah. 2, 2, 3, di-tri-methyl. Yeah. 2, 2, 3, di-tri-methyl. 2, 2, 3, di-tri-methyl. So, this di tri tetra term we do not consider this into alphabetical sequence if the substituents is not complex.