$A$ solution of $(\pm)-2$-chloro-$2$-phenylethane in toluene is mixed slowly with a small amount of $SbCl_5$. The reaction proceeds due to the formation of:

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

$A$ compound $(a)$,$C_8H_9Br$,gives a white precipitate when heated with alcoholic $AgNO_3$. Oxidation of $(a)$ gives an acid $(b)$. The acid $(b)$,$C_8H_6O_4$,easily forms an anhydride on heating. Identify the compound $(a)$.

Analyze the following reaction and identify the nature of $A$ and $B$.

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

The formation of alkene from alkyl halide is an example of