An alkyl halide $X$ $(C_4H_9Br)$ undergoes nucleophilic substitution by $S_N2$ reaction. The product of $X$ on reaction with $Mg/\text{dry ether}$ followed by $D_2O$ is:

Prolonged exposure of chloroform in humans may cause damage to the liver. It is due to the formation of the following compound.

The correct sequence of reagents for the conversion of $X$ to $Y$ is :

Which of the following nucleophiles will show minimum reactivity towards $S_N2$ reaction:

Which among the following compounds undergoes $SN^2$ reaction most rapidly?

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