An organic compound with the molecular formula $C_9H_{10}O$ forms a $2,4-DNP$ derivative,reduces Tollen's reagent and undergoes Cannizzaro reaction; on vigorous oxidation it gives $1,2-$benzenedicarboxylic acid. The structure of the organic compound is:

Given below are two statements,one is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A$: $3$-chloro-$2$-methylpentan-$3$-one can be subjected to Wolff-Kishner reduction to give $3$-chloro-$2$-methylpentane.
Reason $R$: Wolff-Kishner reduction is used to convert $C=O$ into $CH_2$.

The major product $(P)$ in the following reaction sequence is:

What is the product obtained in the reaction of acetaldehyde with semicarbazide?

Methyl vinyl ketone on reaction with $LiCuMe_2$ gives a major product,whose structure is

Which of the following compounds gives the Iodoform reaction?