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Chemistry Paper 4-theory- doubts =D

devilmask123

devilmask123

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can anyone help me with this i dont understand how these diagrams came to be i mean i did study the reactions but these diagrams make no sense to me please help its question no 4
 

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littlecloud11

littlecloud11

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devilmask123 said:
can anyone help me with this i dont understand how these diagrams came to be i mean i did study the reactions but these diagrams make no sense to me please help its question no 4
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For these synthesis, it's always best to go backwards. Start from the products and then find the original compound.
I'd just like to add, the reason the final compound is an ester and not amide is because otherwise the arene would have an-NH3Cl and not an -NH2 group as it was an acid hydrolysis.
 
Zari

Zari

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iKhaled said:
for the second question u have posted..

its the same scenario. first u will see how many hydrogen protons available on each type of proton from the number given at the top of each peak and then u look at the splitting of the peak..from the splitting u will be able to know what is the adjacent type of proton sticking to the one u r trying to find.

now the first peak at 1.2 approx is a triplet which means the adjacent group attached to it must contain 2 hydrogen protons..so it must be CH3 attached to CH2.
the peak at approx 2 is a singlet and has 3 hydrogen protons so it must be attached to attached to to something which doesnt split it like an OH or C=O but it cant be an OH since wdont have any peak that shows OH is present so it will obviously be C=O..from here i started noticing that our organic compound might be an ester since there is a C=O and doesnt have OH and it says 2 oxygen is present in it.. so it can be CH3COOR

now the final peak has 2 hydrogen protons in it and it is split into quartet so it must be next to a group that has 3 hydrogen atoms..from here u can notice our compound will be CH3CH2CO2CH3..got it ?
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iKhaled said:
the final question!!

this one u will not need to use the n+1 rule since there is no splitting so u can say "yaay" no confusing shit in the question..anyway lets look at the peaks!

first peak at 3.8 approx. has 3 hydrogen protons present in it looking in the data booklet is can be R-O-CH3
second peak at 5.5 is as we know obviously the OH peak so R-OH
now the final peak is at approx 6.8 looking in the data booklet thats a benzene ring but notice that it contains 4 hydrogen and not 6 as a regular benzene ring so it has lost 2 hydrogens at 1st and 4th position so it is R-C6H4-R.

now combine all what we got together u will have CH3-O-C6H4-OH..i guess all of them is a singlet peak because if u see all the groups we found are attached to oxygen so they wont have any splitting ( i am kinda sure of that)

i will be glad if i made u understand the 3 questions u have posted hehe :)
Click to expand...
JazakAllah for ur help once again :) this really helped me alot (y) May Allah bless you always :)
 
A

acer4me

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Assalam Alaykum everyone...
I am having big trouble with paper4 especially application questions since we havent been taught dat at sckool! I dnt have time either to read the app booklet. .so I read the book..but questions r rlly tough.. and I realised I need to study some of AS topics for my a2 chem.. since some questions like periodicity come frm AS
Can anyone help me with application plz? and hw do u prepare for paper 4 !?
Thanksin advance. . May Allah help us all
 
K

Khalifa

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

Khalifa

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I would also like to know which important topics to revise from AS. Ive done organic but what else
 
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