Chemistry Physical Chemistry questions from JEE Main 2020.
A cylinder containing an ideal gas ( $0.1mol$ of $1.0d{m}^{3}$ ) is in thermal equilibrium with a large volume of $0.5$ molal aqueous solution of ethylene glycol at its freezing point. If the stoppers ${S}_{1}$ and ${S}_{2}$ (as shown in the figure) are suddenly withdrawn, the volume of the gas in litres after equilibrium is achieved will be _____________. (Given, ${K}_{f}(water)=2.0Kkgmo{l}^{-1},R=0.08d{m}^{3}atm{K}^{-1}mo{l}^{-1})$ 
A flask contains a mixture of compounds $A$ and $B$. Both compounds decompose by first-order kinetics. The half-lives for $A$ and $B$ are $300s$ and $180s$, respectively. If the concentrations of $A$ and $B$ are equal initially, the time required for the concentration of A to be four times that of $B$ (in s) is : $(\mathrm{Use}\mathrm{ln}2=0.693)$