When phenol is heated with phthalic anhydride in presence of conc. ${\mathrm{H}}_2{\mathrm{SO}}_4$, an important acid-base indicator is formed. Identify its structure.

What is $\text{Z}$ in the following sequence of reactions?
$\mathrm{Phenol}\stackrel{\mathrm{Zn} \mathrm{dust}}{\to }\mathrm{X}\stackrel{{\mathrm{CH}}_3\mathrm{Cl}/\mathrm{Anhydrous} {\mathrm{AlCl}}_3}{\to }\mathrm{Y}\stackrel{\mathrm{Alkaline} {\mathrm{KMnO}}_4}{\to }\mathrm{Z}$

Assertion$\left(\mathrm{A}\right):-\mathrm{OH}$ group of phenol is ortho, para directing in electrophilic substitutions

Reason $\left(\mathrm{R}\right):-\mathrm{OH}$ group stabilises the arenium ion formed by the ortho, para attack of the electrophile

The correct answer is

The major product $\left(\mathrm{P}\right)$ formed in the following reaction is

Represent the union of two sets by Venn diagram for each of the following.

$X=\{x | x$ is a prime number between $80$ and $100\}$

$Y=\{y | y$ is an odd number between $90$ and $100\}$

On reacting with neutral ferric chloride, phenol gives

Two aromatic compounds having formula ${\mathrm{C}}_7{\mathrm{H}}_8\mathrm{O}\mathrm{ }$which are easily identifiable by $\mathrm{F}\mathrm{e}\mathrm{C}{\mathrm{I}}_3$ solution test (violet colouration) are

A diazonium chloride reacts with $\mathrm{Ph}\mathrm{-}\mathrm{OH}$ to give an azodye. The reaction is called