A molecule (X) with following structure under mild acidic condition is hydrolysed to produce (Y) and (Z). Identify the correct statements about (Y) and (Z). [figure] Choose the correct answer from the options given below :
- A, B and C Only
- B and C Only
- C and D Only
- A and D Only
Answer
(4) A and D Only
Solution
X is a divinyl-type (enol) ether: CH3-CH=CH-O-C(CH3)=CH2.
Mild acid hydrolysis cleaves the C–O bonds and gives two enols, which tautomerise to carbonyl compounds:
CH3-CH=CH-OH CH3CH2CHO (propanal, Y)
CH2=C(OH)-CH3 CH3COCH3 (propanone, Z)
A: both are C3H6O (58 g mol-1) ⇒ true.
B: neither is an acid, so neither reacts with NaHCO3 ⇒ false.
C: aldehydes are more reactive than ketones towards nucleophilic addition (less steric hindrance, more positive C) ⇒ propanal adds HCN faster ⇒ false.
D: both carbonyl compounds react with 2,4-DNP (addition followed by elimination) ⇒ true.
∴ A and D only.
Answer: (4)