The rate of diffusion of methane at a given temperature is twice that of an unknown gas. The molar mass of unknown gas is

Correct option is C

The correct answer is (c) 64

Explanation:
• According to Graham's Law of Diffusion: r₁/r₂ = √(M₂/M₁)
• Here, rate of CH₄ = 2 × rate of gas and molar mass of CH₄ = 16
• So, 2 = √(M(gas)/16)
• Squaring both sides: 4 = M(gas)/16
• Therefore, M(gas) = 64

Information Booster:
• Methane (CH₄) has a molar mass of 12 + (4 × 1) = 16
• Lighter gases diffuse faster than heavier gases

Additional Knowledge:
8 (Option a)
• Incorrect; would result in a rate √2 times faster than methane

4 (Option b)
• Molar mass of Helium; would diffuse twice as fast as methane

32 (Option d)
• Molar mass of Oxygen; would result in a rate ratio of √2

So the correct answer is (c) 64