(a) Compound $\left(A\right)$ with molecular formula $C_6{H}_{6}O$ gives violet colour with neutral $Fe{Cl}_3$. $\left(A\right)$ reacts with $CH{Cl}_3$ and $NaOH$ gives two isomers $\left(B\right)$ and $\left(C\right)$ with molecular formula $C_7{H}_6{O}_2$. Compound $\left(A\right)$ reacts with ammonia at $473K$ in the presence of $Zn{Cl}_2$ gives compound $\left(D\right)$ with molecular formula $C_6{H}_{7}N$. Compound $\left(D\right)$ undergoes carbylamine test. Identify $\left(A\right),\left(B\right),\left(C\right)$ and $\left(D\right)$ and explain the reactions.
(b) $\left(A\right)$ is reddish brown metal. It belongs to group 11 and period 4 of the periodic table. When heated below $1370K$. $\left(A\right)$ given a black compound $\left(B\right)$. Wnen heated $1370K$ $\left(A\right)$ gives a red compound $\left(C\right)$. With concentrated nitric acid, $\left(A\right)$ liberates ${NO}_2$ gas and gives compound $\left(D\right)$. Identify $\left(A\right),\left(B\right),\left(C\right)$ and $\left(D\right)$. Explain the reactions.