Question

an increase in ______ will increase the solubility of a gas in water.
○ temperature
○ pressure
○ water volume
○ gas volume

Explanation:

To determine the factor that increases gas solubility in water, we analyze each option:

• Temperature: Increasing temperature usually decreases gas solubility in water (e.g., warm soda loses CO₂ faster).
• Pressure: According to Henry's Law, gas solubility in a liquid is directly proportional to the partial pressure of the gas above the liquid. So increasing pressure increases gas solubility (e.g., carbonated drinks are pressurized to dissolve more CO₂).
• Water volume: Solubility is about amount of solute per solvent amount, not total solvent volume. Increasing water volume doesn't increase solubility (it just dilutes if more gas isn't added).
• Gas volume: Solubility depends on pressure/partial pressure, not the volume of the gas itself. Increasing gas volume (at constant pressure) would decrease its partial pressure, reducing solubility.

Answer:

B. pressure