The ratio of the rate of diffusion of helium and methane under indentical conditions of pressure and temperature will be

Options

A. (a) `4`
B. (b) `2`
C. (c) `1`
D. (d) `0.5`

Explanation

To find the ratio of the rate of diffusion of helium and methane under identical conditions of pressure and temperature, we can use Graham's law of effusion, which states that the rate of diffusion of a gas is inversely proportional to the square root of its molar mass.

### Step-by-Step Solution:

1. **Identify the Molar Masses:**
- Molar mass of Helium (He) = 2 g/mol
- Molar mass of Methane (CH₄) = 12 (C) + 4 (H) = 16 g/mol

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