9701 MCQ Solution 62

Question 62: [Organic > Carbonyl Compounds]

The compound hex-3-en-1-ol, P, has a strong ‘leafy’ smell of newly cut grass and is used in perfumery.

P is:        CH₃CH₂CH=CHCH₂CH₂OH

What is produced when P is treated with an excess of hot concentrated acidic KMnO₄?

A CH₃CH₂CH(OH)CH(OH)CH₂CH₂OH

B CH₃CH₂CH=CHCH₂CH₂CO₂H

C CH₃CH₂CHO and OCHCH₂CH₂OH

D CH₃CH₂CO₂H and HO₂CCH₂CO₂H

Reference: Past Exam Paper –June 2003 Paper 1 Q22

Solution 62:

Answer: D.

Double bond breaks. Final carbon in CH₃CH₂CH is bonded to H and C atoms thus, under the said conditions, will oxidise into an aldehyde: CH₃CH₂CHO. Aldehyde will then oxidise into a carboxylic acid: CH₃CH₂CO₂H. Going back to the other product of the initial double bond break, first carbon is bonded to H and C atoms thus, under said conditions, will also oxidise into an aldehyde. Furthermore, the primary alcohol group will also oxidise into an aldehyde, thus producing: HO₂CCH₂CO₂H. These 2 products are only shown in option D, thus making it the correct option.