The rate of diffusion of methane () at a given temperature is exactly twice that of an unknown gas X — States of Matter and Gaseous State Chemistry Question

💡 Solution & Explanation

According to Graham's Law, $r_{CH_4} / r_X = \sqrt{M_X / M_{CH_4}}$. Given $r_{CH_4} = 2 \times r_X$ and $M_{CH_4} = 16\text{ g/mol}$, we have $2 = \sqrt{M_X / 16}$. Squaring both sides gives $4 = M_X / 16 \implies M_X = 16 \times 4 = 64\text{ g/mol}$.