alyoan tariq
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Compound X, C5H12O, is oxidised by acidified sodium dichromate(VI) to compound Y.
Compound Y reacts with butan-2-ol in the presence of a little concentrated sulfuric acid to give
liquid Z.
What could be the formula of Z?
A)CH3(CH2)3CO2CH(CH3)CH2CH3
B)CH3(CH2)3CO2(CH2)3CH3
C)CH3(CH2)2CO2CH(CH3)CH2CH3
D)(CH3)2CHCH2CO2C(CH3)3
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Laurasaur
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(Original post by alyoan tariq)
Compound X, C5H12O, is oxidised by acidified sodium dichromate(VI) to compound Y.
Compound Y reacts with butan-2-ol in the presence of a little concentrated sulfuric acid to give
liquid Z.
What could be the formula of Z?
A)CH3(CH2)3CO2CH(CH3)CH2CH3
B)CH3(CH2)3CO2(CH2)3CH3
C)CH3(CH2)2CO2CH(CH3)CH2CH3
D)(CH3)2CHCH2CO2C(CH3)3
We can assume compound x is either an alcohol or an aldehyde because it can be oxidised by dichromate ions.
Which makes compound y either an aldehyde or a carboxylic acid. As it reacts with an alcohol I'd say it's a carboxylic acid and makes an ester. Since it's a carboxylic acid, the starting alcohol must be a primary alcohol.
Liquid z is an ester of butan-2-ol and the carboxylic acid made.
Spoiler:
Show
Butan-2-ol is CH3CH(OH)CH2CH3
The carboxylic acid made can be either CH3(CH2)3COOH or CH3CH2CH(CH3)COOH (isomers of primary alcohols make the two different carboxylic acids)
The ester produced is either CH3(CH2)3COOCH(CH3)CH2CH3
or CH3CH2CH(CH3)COOCH(CH3)CH2CH3. Since only the first one is in the answers, I'd say it was A.
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alyoan tariq
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(Original post by Laurasaur)
We can assume compound x is either an alcohol or an aldehyde because it can be oxidised by dichromate ions.
Which makes compound y either an aldehyde or a carboxylic acid. As it reacts with an alcohol I'd say it's a carboxylic acid and makes an ester. Since it's a carboxylic acid, the starting alcohol must be a primary alcohol.
Liquid z is an ester of butan-2-ol and the carboxylic acid made.
Spoiler:
Show
Butan-2-ol is CH3CH(OH)CH2CH3
The carboxylic acid made can be either CH3(CH2)3COOH or CH3CH2CH(CH3)COOH (isomers of primary alcohols make the two different carboxylic acids)
The ester produced is either CH3(CH2)3COOCH(CH3)CH2CH3
or CH3CH2CH(CH3)COOCH(CH3)CH2CH3. Since only the first one is in the answers, I'd say it was A.
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hey thank u !!!! i dunno how i cudnt understand such an easy question!!! thanks once again i appreciate it alot !!
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Laurasaur
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(Original post by alyoan tariq)
hey thank u !!!! i dunno how i cudnt understand such an easy question!!! thanks once again i appreciate it alot !!
No problem, sometimes it's just a case of leaving the question and coming back to it later to get a new perspective
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GenericPerson2
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Which exam board / level is this? I do AS level chemistry (OCR) and I the synthetic routes stop at aldehyde... maybe it's in the textbook and I just haven't seen that it reacts with dichromate ions?
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alyoan tariq
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(Original post by GenericPerson2)
Which exam board / level is this? I do AS level chemistry (OCR) and I the synthetic routes stop at aldehyde... maybe it's in the textbook and I just haven't seen that it reacts with dichromate ions?

yea ....1 alcohols oxidise to aldehydes
so basically I don't know if the dichromate ions are ACTUALLY reacting or wait no it doesn't because we just present this reagent by just putting oxygen in brackets
then we just remove a water molecule ...that is why its an agent not a reagent ...
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VanEkerDr
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The dichromate is definitely acting as a reagent. The chromium ions will get reduced in the process.
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