In phenol,electrophilic substitution reaction mainly occurs at which of the following positions?

Phenol $\xrightarrow{NaNO_2/H_2SO_4} B$ $\xrightarrow{H_2O} C$ $\xrightarrow{NaOH} D$. The name of the above reaction is:

One mole of phenol is treated with dilute $HNO_3$ at $298 \ K$ to give a mixture of products. The mixture is separated by steam distillation. The steam volatile compound $(X)$ is separated. The increase in percentage of oxygen in $(X)$ with respect to phenol is . . . . . . $\times 10^{-1}$ %. (Given molar mass in $g \ mol^{-1}$: $H:1, C:12, N:14, O:16$)

In the following reaction:
$C_6H_5CH(CH_3)_2 + O_2$ $\xrightarrow{} C_6H_5C(CH_3)_2OOH$ $\xrightarrow{H^+/H_2O} A + B$
The compounds $A$ and $B$ respectively are $......$

What are $X$ and $Y$ respectively in the following set of reactions?

Some compounds and their $pK_a$ values are given. Arrange them in decreasing order of their acidic strength.
$(i)$ Ethanol $(15.9)$,Phenol $(10.0)$,Cresol $(10.1)$,Water $(15.7)$
$(ii)$ $o$-Nitrophenol $(7.2)$,$m$-Nitrophenol $(8.3)$,Ethanol $(15.9)$,Water $(15.7)$,Phenol $(10.0)$