`100 mL` of hydrogen was confined in a diffusion tube and exposed to air, and at equilibrium, a volume of `26.1 mL` of air was measured in the tube. Again, when `100 mL` of `CO_(2)` was placed in the same tube and exposed to air, `123 mL` of air was measured in the tube at the equilibrium. Find the molecular weight of `CO_(2)`.

Explanation

To solve the problem, we will use Graham's law of diffusion, which states that the rate of diffusion of a gas is inversely proportional to the square root of its molar mass. We will analyze the two cases given in the problem step by step.

### Step 1: Understand the Given Information
- In the first case, 100 mL of hydrogen (H₂) was confined in a diffusion tube, and at equilibrium, 26.1 mL of air was measured in the tube.
- In the second case, 100 mL of carbon dioxide (CO₂) was placed in the same tube, and at equilibrium, 123 mL of air was measured.

### Step 2: Set Up the Ratios for Graham's Law
According to Graham's law, the ratio of the rates of diffusion of two gases is equal to the inverse ratio of the square roots of their molar masses:
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