Question

At T (K) and pressure P, the diffusion rate of an ideal gas is 120 mL min$^{-1}$. What is the time taken (in sec.) for 3000 mL of this gas for diffusion at the same temperature and pressure?

• A. 25
• B. 1500
• C. 250
• D. 150

Hint:

For diffusion at constant temperature and pressure, the time taken for a gas to diffuse is inversely proportional to the diffusion rate.

Answer 1

The Correct Option is B

The diffusion rate is directly proportional to the time taken for diffusion, given constant conditions for temperature and pressure. We know: \[ \text{Rate} = 120 \, \text{mL min}^{-1} \] The time \( t \) for 3000 mL of the gas to diffuse is: \[ t = \frac{\text{Volume}}{\text{Rate}} = \frac{3000 \, \text{mL}}{120 \, \text{mL/min}} = 25 \, \text{min} \] Converting to seconds: \[ t = 25 \times 60 = 1500 \, \text{sec} \] Thus, the time taken is \( \boxed{1500} \, \text{sec} \).