Alkyl Halides Part 2 🔥 | Organic Chemistry | Haloalkanes | JEE Main & Advanced

Added: 2026-04-29

[00:00:00]And I have written here this one chlorobutin and two chlorobutin are known as pi. What is pi? Positional isomers. What is positional isomer?

[00:00:10]When you draw through structure with the same molecular weight but the position of some substituent is different. One chloro two chloro. What is different? Is your chain different? Your chain is same. Your chain is main chain. Remember you will get one more opportunity in this topic to revise your isomear.

[00:00:26]Please use it. This is your main chain.

[00:00:28]This is your main chain. Your chain is same. The branch is chlorine which is in different places. These are known as pi or positional isomers. Simple. Please draw where you have written. Please note down. What is CI?

[00:00:41]When the chain is four member in a straight, three straight one branch.

[00:00:44]These two are called chain isomer. Three in a straight one branch. And then branch CL position is different. That is again pi. And these two things are again we can say CI.

[00:00:56]Okay.

[00:00:58]So once upon a time like they have asked a question on this they have written all four compounds they asked like which is PI of this CI of this and all you can answer easily is that clear any difficulty in this part is it okay you're looking tired it's okay please note down this take your time note down this make very good notes anyway I'll provide all these things but again my notes will not work for you unless until you write once so if it has been written written by you. It will be more easily retained. Okay.

[00:01:34]Is it clear? Everything is fine.

[00:01:39]Great.

[00:01:41]Can you proceed further?

[00:01:45]Okay.

[00:01:50]Write this and try to answer C5 H1 CL. Everybody please take your time. Try to draw. Okay. One more revision of GOC or you can say organic of last year. How do you know that this compound has no double bond or this compound is not having any ring? You have to check that also by default. So remember there is a concept of number of unsaturation.

[00:02:20]degree of unsaturation.

[00:02:22]Okay. Or double bond equivalent.

[00:02:27]Number of unsaturation degree of unsaturation. You may revise already 11th re as I said whenever I'll get any opportunity to revise 11th standard I'll do that. So by the time you complete things you will also revise 11th part also right?

[00:02:53]This is called DBE or double bond equivalent.

[00:03:03]Now these are three different notations for almost same thing they're representing right and there's a formula for all of them which is written as a + 1 minus anybody who can complete this >> very good b minus dx2 what is a in this formula a is number of c atoms what is b in this formula.

[00:03:35]>> Very good. Number of H atoms. Very good.

[00:03:38]>> So can also be right.

[00:03:40]>> Yeah. Yeah. H atoms or X. X as in H hallogen atoms. Right. X screen. Sorry.

[00:03:48]Go.

[00:03:52]Orientation is to be slightly shifted.

[00:03:54]Okay. I'll write it this side.

[00:04:00]Or X. Mostly those will come with a single bond right florine, chlorine, bromine, they will come with a single bond. So they will considered as B only.

[00:04:09]Okay. And D is number of nitrogen atoms or like nitrogen like atom phosphorus arsenic same group members in periodic table.

[00:04:22]Okay, just note down this. Now this is very useful in organic chemistry identification. This is a big savior like lot of help it will give you in terms of understanding just to make you comfortable in this formula. Let's try this formula for methane. All of us know methane has no double bond. Let's apply this formula for methane and see whether it is working or not. So what is a shave? 2.

[00:04:50]Huh?

[00:04:51]A is one. Very good. What is b?

[00:04:56]B is how much?

[00:04:58]>> Hydrogen four. So let's apply 1 + 1 - 4 - how many nitrogen's travel? 0 4 - 0.2. So what's my answer? 2 - 2 0. That means this compound has number of unsaturation 0 degree of unsaturation zero double bond equivalent zero.

[00:05:22]Basically this this not having any unsaturation right. If any compound is having just single bond its number of unsaturation, degree of unsaturation everything will be zero. If it is a double bond, it is counted as one unit.

[00:05:34]If it has a triple bond because of two pi bond two units and if it is a ring structure we ring take as ring as one unsaturation in a way okay for that matter because ring will also reduce two hydrogen's. Whenever you form a ring, it will reduce two hydrogen's.

[00:05:52]Example compound C3 H6 C3 H6 because two hydrogen's can come here.

[00:06:01]Now this is C3 H6.

[00:06:04]What is A value? 3. What is B value? 6.

[00:06:08]So what is answer? 3 + 1 - 6 - 0 by 2.

[00:06:14]What is coming up? 1.

[00:06:17]This one is because of this ring. Okay.

[00:06:20]The ring is also taken as loss of two hydrogen. Had it been C3 H8 then A is three, B is 8. Answer the 3 + 1 - 8 - 0 by 2 that's zero. And that's why this represents a linear chain or maybe a saturated structure. You can see CH3 CH2 CH3. Now somebody can think also sir you have drawn a ring C3H6 can be this compound also CH3 CH double bond CH2 yes that's also correct that's also C3 H6 because that is also one unsaturation one double bond fine any issues with this so either a double bond or a ring will give you one unsaturation shave it shami sanja everybody arav you Shaveya 2 Adya everybody clear comfortable up to this are you understanding everything which we are discussing here online students Chinmai Arjun Niharika any difficulty in this part okay so C5 H1 CL if you try to apply what is your A value five and what is your B value add chlorine also can I say 12 so what's your answer 5 + 1 - 12 - 0 upon 2 is how much is 0 that means all single bonds please attempt this question now is done >> eight aa sir >> eight are eight eight structures eight structures >> so you'll get three from pentine four from butane and two from propane sorry one from propane one from propane Okay, others please try.

[00:08:19]How many got eight answer for the last question?

[00:08:25]Eight.