Arrange the following phenols in decreasing order of their $\mathrm{p} K_a$.

(A) Phenol

(B) ortho - nitrophenol

(C) meta - nitrophenol

(D) para - nitrophenol

Decreasing order of reactivity of the following compounds in the Williamson's ether synthesis is

(II) $\mathrm{Cl}-\mathrm{CH}_2-\mathrm{CH}=\mathrm{CH}_2$

(III) $\mathrm{Cl}-\mathrm{CH}_2-\mathrm{CH}_2-\mathrm{CH}_3$

$$ \text { Identify } X \text { and } Y \text { in the reactions, given below } $$

A primary alcohol was reacted with pyridinium chlorochromate (PCC), which resulted in a product $P$. The product $P$ on treatment with ammonical silver nitrate solution produces