Question

You have a sample of gas that may be either N₂O or toxic H₂S. Testing the effusion of the sample and comparing it to the rate of effusion for N₂, the unidentified gas effuses at 80% the rate of N₂. What is the gas?

Answer 1

Answer: Nitrous Oxide is the gas that effuses at 80% the rate of N₂.

Applying Graham's law of diffusion, we have

= Molecular weight of N₂ / N₂O

= 28/44= 0.636363

Root of ratio of molecular weight of N₂   to N₂O

= $\sqrt{0.636363} = 0.79772$

or 0.79772* 100 = 80%