Which of the following compounds undergoes nucleophilic substitution reaction most easily via the $S_{N}1$ mechanism?

Which of the following would not give $2-$phenylbutane as the major product in a Friedel-Crafts alkylation reaction?

Which of the following phrases are not correctly associated with $S_N1$ reaction?
$(1)$ Rearrangement is possible
$(2)$ Rate is affected by polarity of solvent
$(3)$ The strength of the nucleophile is important in determining rate
$(4)$ The reactivity series is tertiary $>$ secondary $>$ primary
$(5)$ Proceeds with complete inversion of configuration

The compounds $A$ and $B$ in the following reaction are,respectively:
$Benzene$ $\xrightarrow{HCHO + HCl}$ $A$ $\xrightarrow{AgCN}$ $B$

The decreasing order of reactivity of the following organic molecules towards $AgNO_3$ solution is:

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