The intermediate $X$,in the reaction shown below,is ..... .

The major product of the following reaction sequence is:
Aniline $\xrightarrow[(i) NaNO_2, HCl, 273-278K]{(ii) H_2O, warm} \text{Product}$ $\xrightarrow[(iv) NaOH]{(iii) Br_2, (excess)} \text{Product}$ $\xrightarrow{(v) CH_3I} \text{Final Product}$

$A$ solution of phenol in chloroform when treated with aqueous $NaOH$ gives compound $P$ as a major product. The mass percentage of carbon in $P$ is $..............$ (to the nearest integer)
(Atomic mass : $C = 12$; $H = 1$; $O = 16$)

In the reaction sequence,phenol reacts with $HNO_2$ to form $X$,which then reacts with phenol in the presence of $H_2SO_4$ to form $Y$. Identify the major products $X$ and $Y$.

The acidity of the following compounds follows the order:
$I$: Phenol
$II$: $p$-Methoxyphenol
$III$: $p$-Nitrophenol
$IV$: $m$-Nitrophenol

Which reaction is used to prepare $2$-hydroxybenzaldehyde from phenol?