Identify $A$ and $B$ in the following sequence of reaction:

Arrange the following compounds in order of decreasing rate of hydrolysis for $S_{N}1$ reaction:
$(I) \ C_6H_5-CH_2-Br$
$(II) \ p-CH_3-C_6H_4-CH_2-Br$
$(III) \ p-CH_3CH_2-C_6H_4-CH_2-Br$
$(IV) \ p-(CH_3)_2CH-C_6H_4-CH_2-Br$

Which of the following reactions is an example of an $S_{N}2$ reaction?

Which of the following compounds gives a racemic mixture on nucleophilic substitution?
$(a)$ $CH_3-CH(Br)-C_2H_5$
$(b)$ $CH_3-C(Br)(CH_3)-C_2H_5$
$(c)$ $C_2H_5-CH(C_2H_5)-CH_2Br$

Which of the following compounds will undergo racemisation when hydrolysed by an aqueous $KOH$ solution?
$(i)$ $C_6H_5CH_2Cl$
$(ii)$ $CH_3CH_2CH_2Cl$
$(iii)$ $(CH_3)_2CHCH_2Cl$
$(iv)$ $CH_3CH(Cl)C_2H_5$

In the following reactions,
$(i) CH_3-CH(CH_3)-CH(OH)-CH_3 \xrightarrow{H^{+}/\text{heat}} A \text{ [Major product]} + B \text{ [Minor product]}$
$(ii) A$ $\xrightarrow[\text{in absence of peroxide}]{HBr, \text{dark}} C \text{ [Major product]} + D \text{ [Minor product]}$
the major products $(A)$ and $(C)$ are respectively: