An isomer of $C_5H_{12}$ on reaction with $Br_2 / \text{light}$ gave only one isomer $C_5H_{11}Br(X)$. Reaction of $X$ with $AgNO_2$ gave $Y$ as the major product. What is $Y$?

In the given pair of compounds,in which pair is the second compound more reactive than the first toward $S_N2$ reaction?

Which of the following is a polar aprotic solvent?

Which of the following is most reactive towards alcoholic $KOH$?

Among the following chlorides, the compounds which will be hydrolysed most easily and most slowly in aqueous $NaOH$ solution are respectively:
$1$. Methoxymethyl chloride $(CH_3OCH_2Cl)$
$2$. Benzyl chloride $(C_6H_5CH_2Cl)$
$3$. Neopentyl chloride $((CH_3)_3CCH_2Cl)$
$4$. Propyl chloride $(CH_3CH_2CH_2Cl)$

Arrange the compounds of each set in order of reactivity towards $S_{N}2$ displacement:
$(i)$ $2-Bromo-2-methylbutane$,$1-Bromopentane$,$2-Bromopentane$
$(ii)$ $1-Bromo-3-methylbutane$,$2-Bromo-2-methylbutane$,$2-Bromo-3-methylbutane$
$(iii)$ $1-Bromobutane$,$1-Bromo-2,2-dimethylpropane$,$1-Bromo-2-methylbutane$,$1-Bromo-3-methylbutane$.