Q.33. (i) Give the mechanism of cynohydrin formation when acetaldehyde react with HCN in the presence Of NaOH.
(ii) 2-FIuorobutanoic acid is more stronger than 3-Fluorobutanoic acid. Why? (iii)How will you differentiate between 2-pentanone and 3-pentanone?
(iv) How will you convert ethanal to 2-hydroxypropanoic acid?
Answers
Answer:
Mahatma Gandhi
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Explanation:
Answer
(a) - (i) The methyl group due to its +I effect reduce the magnitude of positive charge on carbonyl carbon atom. Moreover, it also hinders the approach of nucleophile CN
−
. Since, in acetaldehyde there is one methyl while in acetone there are two methyl groups attached to crbonyl group therefore acetaldehyde is more reactive than acetone towards nucleophilic addition with HCN.
(ii) Because the release of proton from carboxylic acid is much easier than from phenol as the conjugate base. Carboxylate ion is much more resonance stabilised than conjugate base phenoxide ion.
(b)- (i) Ref. image (ii) Ref. image (iii) Ref. image