The major product $X$ formed in the following reaction is:

The reaction of acetophenone with benzaldehyde in the presence of $HCl$ and heat produces product $(A)$. Identify $(A)$.

The reaction of hydrazine $(NH_2NH_2)$ with aldehydes and ketones yields a compound with the general structure:

Compound $(A)$,$C_6H_{12}O_3$,when treated with $I_2$ in aqueous sodium hydroxide gives a yellow precipitate. When $(A)$ is treated with Tollens' reagent,no reaction occurs. When $(A)$ is hydrolysed and then treated with Tollens' reagent,a silver mirror is formed in the test tube. Compound $(A)$ will be

$CH_3-CH=CH-CH(OH)-CH_3 \xrightarrow{\text{Jones reagent}} X$,
Product $X$ is

Propyne was subjected to a reaction with $HgSO_4/dil. H_2SO_4$,which resulted in a product $P$. The product $P$ was heated with $Ba(OH)_2$ to give the product $Q$. The molecular formula of the product $Q$ is