$C_6H_5CH_2Cl + KCN(aq.) \to X + Y$
Compounds $X$ and $Y$ are

What is the major product formed when $3$-phenylpropene reacts with $HBr$?

Examine the following statements pertaining to an $S_N2$ reaction:
$(1)$ The rate of reaction is independent of the concentration of the nucleophile.
$(2)$ The nucleophile attacks the $C$ atom on the side of the molecule opposite to the group being displaced.
$(3)$ The reaction proceeds with simultaneous bond formation and bond rupture/cleavage.
Amongst the following,which of the above are true?

Predict the correct reactivity order of the following compounds towards $S_N1$ reaction:

$50\%$ of the reagent is used for dehydrohalogenation of $6.45 \ g$ $CH_3CH_2Cl$. What will be the weight of the main product obtained (in $g$)? [At. mass of $H$,$C$,and $Cl$ are $1$,$12$,and $35.5 \ g \ mol^{-1}$ respectively]

At $30\,^\circ C$,the rate of reaction between $2$-bromobutane and $OH^-$ in $75\%$ ethanol and $25\%$ water is given by: $\text{Rate} = 3.20 \times 10^{-5} [2\text{-bromobutane}][OH^-] + 1.5 \times 10^{-6} [2\text{-bromobutane}]$. If $[OH^-] = 1.0\,M$,what percentage of the reaction proceeds via the $S_N2$ mechanism?