Haloalkanes and Haloarene question bank (Chemistry)

$RMgI$ when treated with ice cold water liberated a gas which occupied $1.4\text{ dm}^3/\text{g}$ at STP. The gas produced is further reacted with iodine in presence of $HIO_3$ to give compound (X). Compound (X) in presence of Na and dry ether produced compound (Y). Molar mass of compound (Y) is _______ $\text{g mol}^{-1}$. (Nearest integer)

Consider all the structural isomers with molecular formula $\mathrm{C}_{5} \mathrm{H}_{11} \mathrm{Br}$ are separately treated with $\mathrm{KOH}(\mathrm{aq})$ to give respective substitution products, without any rearrangement. The number of products which can exhibit optical isomerism from these is $\_\_\_\_$.