Q name the alcohol obtained on the reduction of acetaldehyde Q write the reaction for the preparation of butan20l from respective ketone
Answers
Answer:
(i) With increase in +I effect of alkyl groups or increase in the steric hindrance (to the nucleophilic attack by cyanide ion at carbonyl carbon), the reactivity towards HCN addition decreases. Hence, the increasing order of the reactivity towards HCN is Di-tert-butyl ketone > Methyl tert-butyl ketone > Acetone > Acetaldehyde.
(ii) The acid strength of carboxylic acid decreases due to +I effect and increases due to -I effect. Isoprpopyl group has higher +I effect than n propyl group. Hence, 2-methyl propanoic acid is weaker acid than butanoic acid.
With increase in distance, -I effect decreases. Hence, the acid strength of 2-bromobutanoic acid is higher than the acid strength of 3-bromobutanoic acid.
Hence, the increasing order of acid strength is
(CH
3
)
2
CHCOOH<CH
3
CH
2
CH
2
COOH<CH
3
CH(Br)CH
2
COOH <CH
3
CH
2
CH(Br)COOH.