Does anyone why the answer to this a level chemistry question is A

chemist20221

Does anyone why the answer to this a level chemistry question

chemist20221

Which compound could react with both

• K2Cr2O7/H2SO4 in an oxidation reaction and
• an acid catalyst (e.g. H2SO4) in an elimination reaction?

A

B

C

D

Reply 2

Sophi2002

I can't see any structures - maybe try taking a photo or using snipping tool to copy the question ?

General advice - You're looking for a compound which can be oxidised by K2Cr2O7/H2SO4 so Primary alcohol, secondary alcohol, aldehyde and also reacts with H2SO4 so elimination of water so it will be an alcohol I think .

Reply 3

chemist20221

Hi Sophi
It is the question below. What confuses me is that A is correct compound in the attached image because the alcohol can react with the concentrated sulphuric acid to form alkene in an elimination recstion and can be oxidised to ketone but I do not know why B or C are both correct as well.

Screenshot_20220318-150359_OneDrive.jpg141.5KB

Reply 4

Inter_stellar

An alcohol would both undergo oxidation with K2Cr2O7 and elimination (acid catalysed dehydration reaction) using either excess concentrated H2SO4 or H3PO4,

Hope it helps :smile:

Reply 5

Sophi2002

C is a tertiary alcohol so could not be oxidised ( no hydrogen on same carbon available for oxygen to remove).

B would not react with an acid catalyst in elimination because that carbon cannot form a double bond when water is removed ( hard to explain in words but try drawing compound out in displayed formula and trying to take out two hydrogen to form a double bond - the carbons next to it are bonded to alkyl groups not hydrogens so these bonds are too strong to be broken in this reaction)