d
The ideal gas law must hold both before and after the leakage of the gas.
Thus $\frac{P_{i} V}{n_{i} T_{i}}=\frac{P_{f} V}{n_{f} T_{f}}$
$\Longrightarrow n_{f}=\frac{P_{f}}{P_{i}} \frac{T_{i}}{T_{f}} n_{i}$
$\Longrightarrow n_{f}=\frac{1}{2} \frac{273+57}{273+27} n_{i}$
$=\frac{11}{20} n_{i}$
$\Longrightarrow m_{f}=\frac{11}{20} m_{i}$
Thus leaked out mass $=\frac{9}{20} m_{i}=\frac{63}{5} g$