The organic halide, which does not undergo hydrolysis by $\mathrm{S}_{\mathrm{N}} 1$ mechanism is

The reagent ' $X$ ' used in the following reaction to obtain good yield of the product is

Identify the major product $(P)$ in the following reaction sequence.

$$ \left(\mathrm{CH}_3\right)_3 \mathrm{CBr} \xrightarrow[\text { KOH, } \Delta]{\text { Alcoholic }} X \xrightarrow{\mathrm{HBr}} P $$

What is the percentage of carbon in the product ' $X$ ' formed in the given reaction?

$+\mathrm{C}_2 \mathrm{H}_5 \mathrm{Cl} \xrightarrow[\mathrm{AlCl}_3]{\text { Anhydrous }} X$