alleryStart learning →Effusion occurs when a gas passes through an opening of what size?
ALarger than the container itself
BSmaller than the mean free path
CEqual to the molecule's diameter
DLarger than the mean free path
Answer & Solution
Correct answer: B. Smaller than the mean free path
1. The mean free path is the average distance a molecule covers between collisions.
2. If the hole is narrower than that distance, a molecule reaching it has no neighbour close enough to deflect it.
3. Only one particle passes through at a time, which is exactly what effusion means.
4. A wider opening would let the gas stream through in bulk, and that is flow rather than effusion.
_Source: OpenStax Chemistry (CC BY 4.0), Ch 9 "Gases", section 9.4 Effusion and Diffusion of Gases_
Keep practising Gases
Browse all Gases questions for IMU CET, or explore more Chemistry topics.
Related questions
The van der Waals equation reduces to PV = nRT under which condition?A 4.25 L flask holds 3.46 mol of carbon dioxide at 229 degrees C. What pressure does the iIn the van der Waals equation, what does the constant b account for?Who developed the first and simplest equation that improves on the ideal gas law?Under which conditions does a real gas behave most nearly like an ideal gas?For a gas showing perfectly ideal behaviour, the compressibility factor Z takes which valuKinetic molecular theory explains Boyle's law by which change when the volume of a gas decAt a fixed temperature, how do lighter gas molecules compare with heavier ones?