(i) Why pH of reaction should be carefully controlled while preparing ammonia derivatives of carbonyl compound? (ii) Why formic acid is stronger acid than acetic acid

Question

$\begin{array}{1 1}(a) \text{In strongly basic medium ammonia derivatives being basic will react with acids and will not react with carbonyl compound.} \\ (b) \text{In Acidic medium, OH will attack carbonyl group hence pH of a reaction should be carefully controlled.} \\ (c)\text{In basic medium, OH will attack carbonyl group hence pH of a reaction should be carefully controlled.} \\(d)\text{In strongly acidic medium ammonia derivatives being acidic will react with acids and will react with carbonyl compound.} \end{array}$