In the following reaction, condition '$A$' is -

The structure of the compound that gives a tribromo derivative on treatment with bromine water is

What is $Z$ in the following sequence of reactions?
$p-chloronitrobenzene$ $\xrightarrow{NaOH, 443 \ K} X$ $\xrightarrow{(i) Sn + HCl (ii) NaNO_2 / HCl, 0-5^{\circ}C} Y$ $\xrightarrow{H_3O^{+}, 10^{\circ}C} Z$

When phenol is treated with $PCl_5$,the yield of chlorobenzene is generally poor because of the formation of

Which statement is true?

Which one of the following is most reactive towards electrophilic attack?