$C_4H_9Cl$ (Optically Active Compound $A$) $\xrightarrow[DMSO]{NaCN}$ $(R)-2-$methylbutanenitrile; Identify compound $A$?

Which of the following compounds will undergo $S_{N^1}$ reaction most easily?

Arrange the following compounds in order of decreasing rate of hydrolysis for $S_N1$ reaction:
$(i)$ $C_6H_5CH_2Br$
(ii) $p-CH_3-C_6H_4-CH_2Br$
(iii) $p-CH_3CH_2-C_6H_4-CH_2Br$
(iv) $p-(CH_3)_2CH-C_6H_4-CH_2Br$

$2-$Methylpropyl bromide reacts with $C_2H_5O^-$ to give $A$,whereas on reaction with $C_2H_5OH$ it gives $B$. The mechanism followed in these reactions and the products $A$ and $B$ respectively are:

Identify the major product formed from the following reaction: $1$-methylcyclohex-$1$-ene $\xrightarrow[(ii) AgNO_2]{(i) HCl} ?$

Consider the following reactions:
$(a) \; (CH_3)_3CCH(OH)CH_3 \xrightarrow{conc. H_2SO_4} $
$(b) \; (CH_3)_2CHCH(Br)CH_3 \xrightarrow{alc. KOH} $
$(c) \; (CH_3)_2CHCH(Br)CH_3 \xrightarrow{(CH_3)_3CO^{-}K^{+}} $
$(d) \; (CH_3)_2C(OH)CH_2CHO \xrightarrow{\Delta} $
Which of these reaction$(s)$ will not produce Saytzeff product?