The cyanohydrin of a compound X on hydrolysis gives lactic acid; The X...
Explanation:
Cyanohydrin is a compound containing a hydroxyl group (-OH) and a cyanide group (-CN) bonded to the same carbon atom. It is formed by the addition of HCN to a carbonyl group (C=O).
When the cyanohydrin of a compound X is hydrolyzed, it is converted into a carboxylic acid, which is lactic acid in this case. This means that the compound X must contain a carbonyl group (C=O) that reacts with HCN to form the cyanohydrin.
Let's consider the options given:
a) HCHO: Formaldehyde does not contain a carbonyl group. Therefore, it cannot form a cyanohydrin and also cannot give lactic acid upon hydrolysis.
b) CHCHO: Acetaldehyde contains a carbonyl group and can react with HCN to form the cyanohydrin. On hydrolysis, it gives lactic acid. This option is correct.
c) (CH)CO: Propanone (acetone) contains a carbonyl group and can react with HCN to form the cyanohydrin. However, on hydrolysis, it gives a mixture of carboxylic acids, not just lactic acid. Therefore, this option is incorrect.
d) None of these: This option is incorrect as we have already identified that option b is correct.
Therefore, the correct option is b) CHCHO.
The cyanohydrin of a compound X on hydrolysis gives lactic acid; The X...
CH3CHO + HCN → CH3CH(OH)(CN)
CH3CH(OH)(CN) +H2O → CH3CH(OH)COOH or
C3H6O3
This is lactic acid