Question

Argon gas takes $40$ minutes to effuse through a particular orifice, at a certain combination of temperature and pressure. An unknown gas, X, takes $20$ minutes to effuse, through the same orifice, and under the same conditions.
Given the atomic mass of argon is $40amu$, which of the following is the atomic mass of Gas X?

• A. $80amu$
• B. $20amu$
• C. $10amu$
• D. $160amu$

Answer 1

Answer: (D)

$160amu$

$\frac{\text{rate of effusion of Argon}}{\text{rate of effusion of x}}=\frac{\sqrt{M_x}}{\sqrt{M_{\text{Argon}}}}$

putting the values

$\frac{40}{20}=\sqrt{\frac{M_x}{40amu}}$

$M_x=160amu$