What is obtained when toluene is chlorinated in the presence of light and then heated with aqueous $NaOH$?

Observe the following reactions:
$1$. $C_6H_5-CH=CH_2 + HBr \rightarrow X$
$2$. $C_6H_5-C(CH_3)=CH_2 + HBr \rightarrow Y$
$3$. $C_6H_5-CH=CH_2 + HBr \xrightarrow{(C_6H_5COO)_2} Z$
The correct order of reactivity of $X, Y, Z$ towards $S_N1$ reaction is:

The reactivity of ethyl chloride towards nucleophilic substitution is:

The structure of the major product formed in the following reaction is

Identify the catalyst $X$ used in the following reaction: $CH_{3}CH_{2}Br + 2[H] \stackrel{X}{\longrightarrow} CH_{3}CH_{3} + HBr$

In a $S_N2$ substitution reaction of the type $R-Br + Cl^- \xrightarrow{DMF} R-Cl + Br^-$,which one of the following has the highest relative rate?