A gas mixture of equal moles of H 2 and CH 4 is kept in a container fitted with a porous plug. After some time, the gas remaining in the container will be richer in:

H 2 , because it diffuses out faster in most cases

Both will remain in equal proportion under typical conditions

Neither, since the mixture cannot separate according to standard textbooks

A gas mixture of equal moles of H 2 and…

Answer: CH 4 , because H 2 diffuses out faster leaving CH 4 behind.

A H2, because it diffuses out faster in most cases
B CH4, because H2 diffuses out faster leaving CH4 behind
C Both will remain in equal proportion under typical conditions
D Neither, since the mixture cannot separate according to standard textbooks

Correct answer: B. CH4, because H2 diffuses out faster leaving CH4 behind

Explanation: By Graham Law, the lighter gas H2 effuses out faster through the porous plug, so the container becomes richer in the heavier CH4.

Graph of pressure versus volume for a fixed amount of gas at constant temperature: the curve falls steeply then flattens, a hyperbola showing pressure inversely proportional to volume.

Boyle's law: at constant temperature the pressure of a fixed mass of gas is inversely proportional to its volume (P ∝ 1/V), so the P–V plot is a hyperbola — halving the volume doubles the pressure. Image: Reginaprice2013, CC BY-SA 3.0, via Wikimedia Commons.

Concept context

Discover why gases expand to fill any container while liquids flow and solids hold their shape. Master the gas laws, the ideal gas equation, and the reasons real gases deviate from ideal behavior.

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A gas mixture of equal moles of H<sub>2</sub> and CH<sub>4</sub> is kept in a container fitted with a porous plug. After some time, the gas remaining in the container will be richer in:

Concept context

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