Statement I: Semicarbazide is H2N−NH−C(=O)−NH2. The lone pair on the −NH2 group attached to the carbonyl carbon is involved in resonance with the C=O group, making it less nucleophilic. Therefore, the −NH2 group attached to the −NH− group acts as the nucleophile. The condensation of acetaldehyde (CH3−CH=O) with semicarbazide under optimum pH (around 3.5) yields acetaldehyde semicarbazone, CH3−CH=N−NH−C(=O)−NH2. Thus, Statement I is true.
Statement II: The molecule Ph−CH(OH)(OCH3) is a hemiacetal. Hemiacetals are unstable and readily undergo hydrolysis in the presence of dilute acid to yield the corresponding aldehyde and alcohol. Hydrolysis of Ph−CH(OH)(OCH3) gives benzaldehyde (Ph−CH=O) and methanol (CH3OH). Thus, Statement II is also true.
Both Statement I and Statement II are true.
Answer: Both Statement I and Statement II are true