Chloroethane with silver acetate forms $X$ and with $LiAlH_4$ forms $Y$. What are $X$ and $Y$?

Identify the product $B$ in the following reaction sequence:
$1$-bromo-$4$-chlorobenzene $\xrightarrow[\text{Dry ether}]{Mg (1 \text{ equivalent})} (A)$ $\xrightarrow{HO-CH_2-CH_2-Cl} (B)$

Which one of the following compounds is most reactive towards $S_N1$ reaction?

Match the reactions in List-$I$ with the features of their products in List-$II$ and choose the correct option.
| List-$I$ | List-$II$ |
| :--- | :--- |
| $(P)$ $(-)-1$-Bromo-$2$-ethylpentane $\xrightarrow{aq. NaOH, S_N2}$ | $(1)$ Inversion of configuration |
| $(Q)$ $(-)-2$-Bromopentane $\xrightarrow{aq. NaOH, S_N2}$ | $(2)$ Retention of configuration |
| $(R)$ $(-)-3$-Bromo-$3$-methylhexane $\xrightarrow{aq. NaOH, S_N1}$ | $(3)$ Mixture of enantiomers |
| $(S)$ $(3S, 5S)-5$-bromo-$3$-methylheptane $\xrightarrow{aq. NaOH, S_N1}$ | $(4)$ Mixture of structural isomers |
| | $(5)$ Mixture of diastereomers |

The final product formed when ethyl bromide is treated with excess of alcoholic $KOH$ is

Compare the relative rate of reaction with $H_2O$ for the following compounds: