720cc of methane diffused through a porous membrane in 30min. Under identical conditions 240cc of gas 'X'diffused in 20 min. Calculate the molecular weight of 'X'.

Explanation

To solve the problem, we will 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 molecular weight.

### Step-by-Step Solution:

1. **Determine the Rate of Diffusion for Methane (CH₄)**:
- Given that 720 cc of methane diffused in 30 minutes, we can calculate the rate of diffusion (R₁) as follows:
\[
R_1 = \frac{\text{Volume of CH}_4}{\text{Time}} = \frac{720 \text{ cc}}{30 \text{ min}} = 24 \text{ cc/min}
...