Ans: (A)
Let mass of ethane and \(\mathrm{H}_{2}\) are \(\mathrm{x} \mathrm{g}\).
$$
\mathrm{n}_{\mathrm{H}_{2}}=\frac{\mathrm{x}}{2} \text { and } \mathrm{n}_{\mathrm{C}_{2} \mathrm{H}_{\mathrm{G}}}=\frac{\mathrm{x}}{30}
$$
$$
\frac{P_{H_{2}}}{P_{T}}=\frac{n_{H_{2}}}{n_{H_{2}}+n_{C_{2} H_{3}}}=\frac{\frac{x}{2}}{\frac{x}{2}+\frac{x}{30}}=\frac{15}{16}
$$