$A$ solution of $(\pm)-2$-chloro-$2$-phenylethane in toluene is mixed slowly with a small amount of $SbCl_5$. The reaction proceeds due to the formation of:

Arrange the following alkyl halides in the increasing order of their reactivity towards nucleophilic substitution reaction:
$(I)$ $CH_3CH_2CH(Cl)CH_3$
$(II)$ $CH_2=CHCH(Br)CH_3$
$(III)$ $CH_2=CHCH(Cl)CH_3$
$(IV)$ $CH_3CH=C(Br)CH_3$

Where $Nu =$ Nucleophile. Find out the correct statement from the options given below for the above $2$ reactions.

An organic compound $X$ $(C_7H_7Cl)$ when reacted with $KCN$ in $C_2H_5OH$ gives a major product $Y$. $Z$ is formed when $Y$ is reduced with $LiAlH_4$. What are $Y$ and $Z$?

In solvolysis of $1,2$-dimethylpropyl $p$-toluenesulfonate in acetic acid at $75^\circ C$,(alkene + substitution products) will be formed by which mechanism?

Iodoethane reacts with sodium in the presence of dry ether. The product is