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OCR F324-June 2013 Chemistry

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how many carbon environments in 1,2-dimethylbenzene, 1,3-dimethylbenzene and ethylbenzene??? thanks
Original post by otrivine
quick question

http://www.ocr.org.uk/Images/65129-question-paper-unit-f324-rings-polymers-and-analysis.pdf

why is it only aspirin reacts with the Na2CO3 cause both compounds consist of carbonyl groups/?


It's because the COOH reacts with it to make a salt, CO2 and H2O. Phenol is too weak of an acid to actually react with NaCO3. This is actually a test to tell them apart because the one with COOH will fizz
Reply 1902
Avatar for Raj Kang
Raj Kang
Original post by wl1
Great, thanks. So -NH and -OH protons will have singlet splitting patterns even if they are adjacent to a carbon with a proton?



Yes unless if they state in the question using d20 by proton exchange these peaks will no give of a peak once d20 is added
Reply 1903
Avatar for otrivine
otrivine
OP
14
Original post by Strawberry x3
It's because the COOH reacts with it to make a salt, CO2 and H2O. Phenol is too weak of an acid to actually react with NaCO3. This is actually a test to tell them apart because the one with COOH will fizz


I see if they ask us why this can react with Na2co3 and that cant, what should we say?
Reply 1904
Avatar for clard254
clard254
Original post by Meado123


This question doesn't give information on the whole spectrum but since they said there is doublet at chemical shift 0.9 of area 6, the aldehyde has two methyl groups bonded to CH the only aldehyde with the given molecular formula and that sequence is(CH3)2CHCH2CHO

hope that helps :smile:
Original post by AFC_123456789
how many carbon environments in 1,2-dimethylbenzene, 1,3-dimethylbenzene and ethylbenzene??? thanks


4/4/6 I think :smile:
Reply 1906
Avatar for Meado123
Meado123
Original post by clard254
This question doesn't give information on the whole spectrum but since they said there is doublet at chemical shift 0.9 of area 6, the aldehyde has two methyl groups bonded to CH the only aldehyde with the given molecular formula and that sequence is(CH3)2CHCH2CHO

hope that helps :smile:


Thankyou, yes i understand now :smile:
Just say that COOH is strong enough to react with NaCO3 while phenol isn't :smile: I think.
Reply 1908
Avatar for mrmccarl
mrmccarl
can someone please tell me all the reagents and conditions we are expected to know for the exam?
Reply 1909
Avatar for D4rth
D4rth
9
Original post by mrmccarl
can someone please tell me all the reagents and conditions we are expected to know for the exam?

Its been posted, check the previous recent post for a massive list.

They are in the textbook too summarised if you looked at the synthesis topic.

Posted from TSR Mobile
Reply 1910
Avatar for Sly1
Sly1
6
(CH3CO)2O + C6H5OH is a nice ester formation question
Reply 1911
Avatar for Jamie66
Jamie66
Original post by AFC_123456789
how many carbon environments in 1,2-dimethylbenzene, 1,3-dimethylbenzene and ethylbenzene??? thanks


I make it 4, 5, 6 :smile:
Original post by Raj Kang
2,4 dinitophenylhydrazine + methanol + sulpuhric acid = bradys


i think 2,4-dnp is ok
Reply 1913
Avatar for Zzzyax
Zzzyax
2
Original post by otrivine
quick question

http://www.ocr.org.uk/Images/65129-question-paper-unit-f324-rings-polymers-and-analysis.pdf

why is it only aspirin reacts with the Na2CO3 cause both compounds consist of carbonyl groups/?


its not about the carbonyl C=O, that part does not react with the carbonate.

rememeber that it is acid +carbonate that reacts to from salt and water

in reactions of phenols, phenol is a very weak acid , phenol cannot react with carbonates.


remember that :

phenol +carbonate --->no reaction

phenol + metal e.g. Na --> reaction

edit :i think that right, correct me if im wrong
(edited 10 years ago)
Reply 1914
Avatar for otrivine
otrivine
OP
14
http://www.ocr.org.uk/Images/59704-mark-scheme-unit-f324-rings-polymers-and-analysis-june.pdf

question 2)c)i

why do they not put on both sides O-Na+

is because it can form no charge overall?
Reply 1915
Avatar for otrivine
otrivine
OP
14
Original post by Zzzyax
its not about the carbonyl C=O, that part does not react with the carbonate.

rememeber that it is acid +carbonate that reacts to from salt and water

in reactions of phenols, phenol is a very weak acid , phenol cannot react with carbonates.


remember that :

phenol +carbonate --->no reaction

phenol + metal e.g. Na --> reaction



thank you

but please describe why
5 days revision,need a B atleast :s-smilie:
Reply 1917
Avatar for Zzzyax
Zzzyax
2
Original post by otrivine
thank you

but please describe why


like i said phenol is such a weak acid it cannot react with carbonates, just remember that.
Reply 1918
Avatar for mrmccarl
mrmccarl
Original post by D4rth
Its been posted, check the previous recent post for a massive list.

They are in the textbook too summarised if you looked at the synthesis topic.

Posted from TSR Mobile


cheers.
Reply 1919
Avatar for mrmccarl
mrmccarl
anyone else feeling depressed after that C4 maths exam?

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