The electrophile involved in the Reimer-Tiemann reaction is

Product $(A)$ and $(B)$ respectively are :-

Reaction of phenol with $NaOH$ followed by heating with $CO_{2}$ under high pressure,and subsequent acidification gives compound $X$ as the major product,which can be purified by steam distillation. When reacted with acetic anhydride in the presence of a trace amount of conc. $H_{2}SO_{4}$,compound $X$ produces $Y$ as the major product. Compound $Y$ is $....$

Electrophilic substitution reaction in phenol takes place at:

Identify $X$ and $Y$ in the following reaction:
$X \xrightarrow{Y} \text{Benzoquinone}$

The order of acidic strength of $X, Y$ and $Z$ is:
Phenol reacts with dilute $HNO_3$ to form $X$ ($o$-nitrophenol) and $Y$ ($p$-nitrophenol). Phenol reacts with concentrated $HNO_3$ and $H_2SO_4$ to form $Z$ ($2,4,6$-trinitrophenol or picric acid).