Which of the following gases would diffuse about one-third as fast as helium gas, He? A)HCl B)NH₃ C)CH₄ D)H₂O

Question

Quizplus · Accepted Answer

According to Graham's law of effusion, the rate of effusion of a gas is inversely proportional to the square root of its molar mass. Helium (He) has a molar mass of approximately 4 g/mol. For a gas to diffuse about one-third as fast as helium, its molar mass would need to be about 9 times that of helium (since the rate is inversely proportional to the square root of the molar mass, and $ \sqrt{9} = 3 $). Hydrogen chloride (HCl) has a molar mass of approximately 36.5 g/mol, which is close to 9 times the molar mass of helium, making it the correct choice.

Which of the Following Gases Would Diffuse About One-Third as Fast