Which halide will be least reactive in respect to hydrolysis?

In an $S_N2$ reaction on a chiral carbon atom,what is always produced?

Polysubstitution is a major drawback in

$2CHCl_3 + O_2 \xrightarrow{X} 2COCl_2 + 2HCl$. In the above reaction,$X$ stands for:

Given below are two statements $:$
Statement $(I) :$ Alcohols are formed when alkyl chlorides are treated with aqueous potassium hydroxide by elimination reaction.
Statement $(II) :$ In alcoholic potassium hydroxide,alkyl chlorides form alkenes by abstracting the hydrogen from the $\beta-$carbon.
In the light of the above statements,choose the most appropriate answer from the options given below $:$

Ethyl bromide reacts with alcoholic $KOH$ to give.....