• We need your support!

    We are currently struggling to cover the operational costs of Xtremepapers, as a result we might have to shut this website down. Please donate if we have helped you and help make a difference in other students' lives!
    Click here to Donate Now (View Announcement)

Chemistry: Post your doubts here!

Messages
136
Reaction score
164
Points
43
Why don't we put Br to the ring with ester?? June 2014 /42
Plz help!!
 

Attachments

  • image.jpg
    image.jpg
    161.5 KB · Views: 13
Messages
162
Reaction score
249
Points
53
well i think u would only lose marks for accuracy but even some people did get 29.5 from ur centre and ur average titre is 29.4, so i think then it's fine... u dont need to worry that much...you will probably get good marks insha allah(y)(y):X3:
inshallah your cousin too, thanks that made me feel better.
 
Messages
136
Reaction score
164
Points
43
Benzene does not react with bromine water, pure bromine and anyhdyrous FeBr3 is required in order for the benzene ring to react.
But the other Beene with OH is reacting.. I know it's a ring activator but won't the oxygen of ester activate the ring too?
CONFUSED
 
Messages
1,983
Reaction score
3,044
Points
273
But the other Beene with OH is reacting.. I know it's a ring activator but won't the oxygen of ester activate the ring too?
CONFUSED
I don't know exactly what conversation is going on so sorry to interrupt but the oxygen of the ester would not be bonded directly to the benzene ring. it would be bonded to a carbon atom which would be bonded to the ring.
 
Messages
136
Reaction score
164
Points
43
I don't know exactly what conversation is going on so sorry to interrupt but the oxygen of the ester would not be bonded directly to the benzene ring. it would be bonded to a carbon atom which would be bonded to the ring.
I am confused in the ring on the top which has oxygen direct,y attached to it
 
Messages
5,330
Reaction score
11,839
Points
698
I have a couple of questions which I was hoping somebody could help me out with.

1- Any notes on the Soil treatment(sorbents and stuff) and nano technology of applications, I got less time so something short will be appreciated.

2- I just want to confirm the conditions for ester hydrolysis. is it the same as that of hydrolysis of an amide linkage?
 
Messages
1,983
Reaction score
3,044
Points
273
I have a couple of questions which I was hoping somebody could help me out with.

1- Any notes on the Soil treatment(sorbents and stuff) and nano technology of applications, I got less time so something short will be appreciated.

2- I just want to confirm the conditions for ester hydrolysis. is it the same as that of hydrolysis of an amide linkage?
you can revise the application chapter 3 from chemguideforcie.co.uk much quicker than from other places because he has given the reference to all of the latest exam questions and what was asked in them. which means you will be able to revise everything that has come in exams till now.
yes. the conditions+reagent for hydrolysis are 'dilute HCL(aq) or H2SO4(aq) + heat' or you can write H+(aq) + heat
 
Messages
5,330
Reaction score
11,839
Points
698
another thing:

when we use KMnO4 on alkyl benzene.

say we had benezene-CH2CH3.
what would be the product?
benzene-COOH or benzene-CH2COOH

also:

halogenation of phenol has 2 cases,
one where Br(l) in a non-polar solvent is used. a mixture of 2-bromo phenol and 4-bromo phenol is produced


and one Br(aq)
2,4,6, bromo phenol produced.

is this correct?

btw.. thank you soo much Suchal Riaz
I remember you from last year bro,
congrats soo much on your distinction(saw your name in the list in feb and was soo happy for you). MashAllah! :D
 
Messages
1,983
Reaction score
3,044
Points
273
I am confused in the ring on the top which has oxygen direct,y attached to it
This was actually a blunder CIE made. They shouldn't have given this question because average students dont know that in COO there is a delocalisation between COO like this:
upload_2015-5-10_0-18-32.png
so the lone pair that is actually donated to the ring is used up in this delocalisation that means that the ring isn't 'activated' as you call it.
 
Messages
1,983
Reaction score
3,044
Points
273
another thing:

when we use KMnO4 on alkyl benzene.

say we had benezene-CH2CH3.
what would be the product?
benzene-COOH or benzene-CH2COOH

also:

halogenation of phenol has 2 cases,
one where Br(l) in a non-polar solvent is used. a mixture of 2-bromo phenol and 4-bromo phenol is produced
On wikipedia it says that the reaction is faster in polar solution so in water it would be faster so there is more chance of 2,4,6. but if you use non-polar solvent and heat it and have Br2 in high concentration you can still get 2,4,6.


and one Br(aq)
2,4,6, bromo phenol produced.

is this correct?

btw.. thank you soo much Suchal Riaz
I remember you from last year bro,
congrats soo much on your distinction(saw your name in the list in feb and was soo happy for you). MashAllah! :D
When an alkyl is attached to a benzene ring directly it would be converted into benzoic acid. no matter what that alkyl. it would always be upload_2015-5-10_0-22-36.png

(2) as far as I know a concentrated or heated Br2(aq) would produce 2,4,6 but milder conditions would produce just 2 or 4

(3)Thank you. If you have any other doubts please let me know.
 
Messages
69
Reaction score
59
Points
28
I have a couple of questions which I was hoping somebody could help me out with.

1- Any notes on the Soil treatment(sorbents and stuff) and nano technology of applications, I got less time so something short will be appreciated.

2- I just want to confirm the conditions for ester hydrolysis. is it the same as that of hydrolysis of an amide linkage?
Ester hydrolysis requires reflux whereas amide hydrolysis does not.
 
Messages
136
Reaction score
164
Points
43
This was actually a blunder CIE made. They shouldn't have given this question because average students dont know that in COO there is a delocalisation between COO like this:
View attachment 53352
so the lone pair that is actually donated to the ring is used up in this delocalisation that means that the ring isn't 'activated' as you call it.
Okay thanks a lot
 
Messages
1,983
Reaction score
3,044
Points
273
Ester hydrolysis requires reflux whereas amide hydrolysis does not.
reflux actually depends on the reagents. if the products/reactants are volatile they need reflux. otherwise not. if there is a very complex and large molecule with ester links it would not need reflux just heat because it wouldn't evaporate. small esters such as ethyl ethanoate must need reflus as both products and reactants are very volatile. they evaporate even without heating.
 
Top