Which of the following compounds will form a precipitate most readily with $AgNO_3$?

The following is a substitution reaction in which $-CN$ replaces $-Cl$:
$R-Cl \xrightarrow[\text{alcoholic}]{KCN, \Delta} R-CN + KCl$
To obtain propanenitrile,$R-Cl$ should be:

What is dehydrohalogenation?

In the given pair of compounds,in which pair is the second compound more reactive than the first toward $S_N2$ reaction?

$n$-propyl bromide on treatment with ethanolic potassium hydroxide produces

Hydrolysis of an alkyl bromide $X$ $(C_5H_{11}Br)$ follows first-order kinetics. Reaction of $X$ with $Mg$ in dry ether followed by treatment with $D_2O$ gives $Y$. What is $Y$?