From a certain apparatus, the diffusion rate of hydrogen has an average value of `28.7 cm^(3) s^(-1)`. The diffusion of another gas under the same condition is measured to have an average rate of `7.2 cm^(3) s^(-1)`. Identify the gas.

Explanation

To identify the unknown gas based on its diffusion rate compared to hydrogen, we can use Graham's law of effusion/diffusion. Here is a step-by-step solution:

### Step 1: Write down Graham's Law
Graham's law states that the rate of diffusion of a gas is inversely proportional to the square root of its molar mass. Mathematically, it can be expressed as:
\[ \frac{r_1}{r_2} = \sqrt{\frac{M_2}{M_1}} \]
where:
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