Gas solubility and pressure — At a fixed temperature, how does the solubility of a gas in a liquid solvent change as pressure increases?

Introduction:
Design of absorbers, carbonation processes, and oxygenation systems relies on understanding how gas solubility varies with pressure at constant temperature.

Given Data / Assumptions:

• Temperature is held constant.
• Dilute gas conditions where Henry’s law applies.
• Solvent non-reactive with the gas.

Concept / Approach:
Henry’s law states that at constant temperature, the dissolved concentration of a gas in a liquid is proportional to its partial pressure in the gas phase: C = k_H * p_g (using an appropriate convention). Therefore, increasing the gas pressure increases p_g and thus increases the equilibrium solubility.

Step-by-Step Solution:
Identify applicable regime: dilute, non-reactive gas in liquid.Apply Henry’s law: C ∝ p_g at fixed T.Conclude that solubility increases with pressure.

Verification / Alternative check:
Practical examples include carbonated beverages being bottled under pressure to increase CO2 solubility.

Why Other Options Are Wrong:

• (b), (d) Contradict Henry’s law trend.
• (c) Would only be true if pressure had no effect, which is not the case in this regime.
• (e) Henry’s constant remains central to the relationship.

Common Pitfalls:
Confusing Henry’s law (gas solubility) with Raoult’s law (solvent vapor pressure); forgetting temperature’s influence on k_H.

Final Answer:
Increases