Chemistry Paper 4-theory- doubts =D

[nishan2052]

how halogen atom in halogenoarene overlaps pi bonding system?

 

[nishan2052]

No dude..you forgive me..cz u came here 4 answers nt the shoot* i offer
jk
Welcome to XPC!!!!!

 

[iKhaled]

how halogen atom in halogenoarene overlaps pi bonding system?

it has a long pair that gets withdraw into the aryl ring (full of electrons) and overlaps with it..got it ?

 

[knowitall10]

Lome pair* Brother iKhaled

 

[iKhaled]

Lome pair* Brother iKhaled

lone* faaaiill u too

 

[Tkp]

Lome pair* Brother iKhaled

help me in o/n 06
3b

 

[iKhaled]

help me in o/n 06
3b

too lazy to get the link..its ur job to post a link!! then we may help u if we can

 

[Tkp]

too lazy to upload a link

 

[iKhaled]

too lazy to upload a link

LOL ok then we both lazy..dats good

 

[nishan2052]

please tell me why different grp r attached at different place in benzene ring?

 

[knowitall10]

lone* faaaiill u too

Lol!

 

[acer4me]

Hi guys. Can someone please tell me why first electron affinity is exothermic while the second one is endothermic?

Well khalifa..
U see; 1st is either exo or endo
But 2nd electron affinity is ALWAYS endo.. why? Because u are adding an extra electron...it might mean u are adding an extra shell ...that requires alooot of energy to overcome the repulsion that already occurs between negative electrons..
inshallah my answer is clear to u bro !

 

[nishan2052]

why my post is not replied? plz anyone reply

 

[acer4me]

please tell me why different grp r attached at different place in benzene ring?

Nishan :


Some groups are called electron donating and others are called electron withdrawing

Electron donating groups include CH3- , OH-
Electron withdrawing include COOH , NO2

However idk whether NH2 is EW or ED
Can anyone help plz?

Electron donating activate 2, 4, 6 positions on benzene ringh for othr grps to b attached
Electron withdrawing activate 1, 3, 5

 

[acer4me]

I researched. .its electron donating group. .bcz of itz lone pair

 

[kelly sheers]

I researched. .its electron donating group. .bcz of itz lone pair

yes sorry It does withdraw electrons from its third bond, but at the same time the high electron density around the N (it has a lone pair) feeds back into the bond, causing the overall effect to be activating (electron donating). Compare this with -NO2, which is deactivating-the lone pair doesn't exist any more since both "lone" valence electrons are now used in double bonds with oxygen. Then the electronegativity of N does cause deactivation. therefore electron donating

 

[acer4me]

PLEASE HELP ME WITH THIS QUESTION
JUNE 07/ PAPER 4
Nmbr 4 part (c)
!!!

 

[donorsolutions]

yes sorry It does withdraw electrons from its third bond, but at the same time the high electron density around the N (it has a lone pair) feeds back into the bond, causing the overall effect to be activating (electron donating). Compare this with -NO2, which is deactivating-the lone pair doesn't exist any more since both "lone" valence electrons are now used in double bonds with oxygen. Then the electronegativity of N does cause deactivation. therefore electron donating

plz can u explain the mechanism in this question 3 c(iii) . i am having trouble understanding it is this thing even in our syllabus ??
http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_s12_qp_42.pdf

 

[nishan2052]

plz help me with this alpha and beta structure of protein.

 

[littlecloud11]

plz help me with this alpha and beta structure of protein.

http://www.chemguide.co.uk/organicprops/aminoacids/proteinstruct.html
This explains it pretty well.