JEE Chemistry Club

4:52 AM

Can anyone help me comment on option A question 39 here please?

imgur.com/a/FRSY6

I know vapor density is directly proportional to molar mass, but then what? We don't know molar mass of A, B, C :(

5:38 AM

Gud question

@GaurangTandon v.d prop to moles

Since the reaction is I presume balanced the masses on both the sides are the same

Total mass /4 < total mass / 3

5:59 AM

@GaurangTandon Is there no "upload" option in mobile?

IIRC, there was one

@AvnishKabaj vapour density is inversely proportional to moles

@GaurangTandon Btw, why is option D incorrect?

6:22 AM

@Abcd no :'(

@Abcd this is multicorrect question, BD both are correct. I haven't yet told whether if A is right or wrong ;)

@AvnishKabaj inversely, I agree with Abcd

Anyway that gives the answer. Since moles in the reaction increase, vapor density decreases

Good good thanks guys!

6:40 AM

@GaurangTandon You had marked it incorrectly there so I got confused.....Now why is option A incorrect, moles are increasing so VD should decrease right?

@GaurangTandon So ABD should be correct IMO

@Abcd yep that's right. Good

@Abcd ya I wrote that wrong

2 hours later…

8:33 AM

@AvnishKabaj @GaurangTandon ^

Is this an SN2 reaction? If yes, then I doubt there would be "inversion" in it.

8:56 AM

@Abcd what's the pro-duct

And do you have another exam this Sunday
?

I do

@AvnishKabaj Its the same for all Fiitjees in India

Noice

@Abcd 2 methoxyphenol 3 methoxyphenol phenol?

Which 1

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@AvnishKabaj Methoxy benzene + methyl sulfate anion

Ya I was sort of confused

@AvnishKabaj For allyl bromide + OR- , what would you predict? $S_N1$ or $S_N2$

9:03 AM

I'm still thinking

Definitely not SN2

@AvnishKabaj In clayden its given as SN2

Now I am confused how

@Abcd ¯\_(ツ)_/¯

What does dimethyl sulphate do?

@Abcd that's SN2

3 mins ago, by Avnish Kabaj

Definitely not SN2

@AvnishKabaj why?

Dude

I'm reading up dimethyl sulphate

Gimme a sec

@Abcd gotit want a mechanism

@AvnishKabaj he has given the mechanism.

My question is that is this SN2 with respect to Oxygen?

38 mins ago, by Abcd

Is this an SN2 reaction? If yes, then I doubt there would be "inversion" in it.

9:16 AM

@Abcd yes it's SN2

@AvnishKabaj its SN2 without inversion right?

Inversion only happens when the carbon atom is tetra valent

Because O isnt a chirality centre

Yeah

14 mins ago, by Abcd

@AvnishKabaj For allyl bromide + OR- , what would you predict? $S_N1$ or $S_N2$

9:17 AM

@Abcd strong bases always do SN2

I would say SN2

@AvnishKabaj but allylic cations are so stable

why not SN1

@Abcd nothing is promoting sn1

@AvnishKabaj allylic carbocations are stable!

@Abcd So what!!!!!!!

Just because I can run to my school doesn't mean I do that

I use my car

@AvnishKabaj So SN1 because stable carbocation will be formed then attacked ...

9:21 AM

@Abcd what is promoting the formation of the carbocation?

Bonds don't break jlt

2 hours later…

11:09 AM

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Fluoroantimonic acid

Fluoroantimonic acid is an inorganic compound with the chemical formula H2FSbF6 (also written H2F[SbF6], 2HF·SbF5, or simply HF-SbF5). It is an ionic liquid produced by treating hydrogen fluoride (HF) with antimony pentafluoride (SbF5) in a stoichiometric ratio of 2:1. It is the strongest superacid. It is particularly corrosive and toxic. It has been shown to protonate even hydrocarbons to afford pentacoordinate carbocations. Similar acids can be created by using excess antimony pentafluoride. The reaction to produce fluoroantimonic acid is: SbF5 + 2 HF → SbF−6 + H2F+ The acid is often said to...

12:05 PM

@Abcd Me2SO4 used in the reaction is a methylating agent

-OH converts to -OMe

i don't know of the mechanism though

@GaurangTandon 12th portion? Which chapter?

@GaurangTandon I got the mechanism ...

@Abcd idk, why does it matter? just a single reagent, not a whole chapter. Mug it up!

@GaurangTandon but you must have first been told about it somewhere.

I am interested to know about that

just came across it in MS Chouhan, don't recall when or where

Okay

12:13 PM

oh thanks!

12:34 PM

@GaurangTandon I can't understand how Hammond's postulate explains Zaitsev's rule

@Abcd i'm sure Hammond's postulate wasn't supposed to explain that?

@GaurangTandon Page 302 of MS chauhan Slomon Frhyle

the way I think it worked was that a less bulky base can easily approach hindered hydrogen atoms and form a more substituted alkene

a bulky base cannot

@Abcd oh, i'll have to read it then. I've a test tomo, so you'll have to wait I guess :/

5 hours later…