$2-$pentanone can be distinguished from $3-$pentanone by the reagent:

In the following reaction,'$A$' is

The enolate ion that reacts with $3-$buten$-2-$one to form $(Y)$ is

An organic compound $A$ has the molecular formula $C_3H_6O$ and it undergoes the iodoform test. When saturated with dilute $HCl$,it gives $B$ with the molecular formula $C_9H_{14}O$. $A$ and $B$ respectively are:

The reaction shown below proceeds via which mechanism?

Compound $(A)$ with molecular formula $C_{11}H_8O$ does not undergo self-aldol condensation. Upon ozonolysis,it yields $Ph-CHO$ and $2B$,where $B$ on oxidation with $Ag^{+}$ gives oxalic acid. Identify compound $(A)$.