State Henry's law and give its application to gas solubility in liquids.

• A. C = kH P; the concentration of a dissolved gas is proportional to its partial pressure in the gas phase.
• B. C = kH P; the concentration of a dissolved gas is proportional to its partial pressure, with constant kH.
• C. Henry's law relates temperature to solubility but not pressure.
• D. Henry's law applies only to solids dissolving in water.

Answer: (D)

Henry's law states that, at a constant temperature, the amount of gas that will dissolve in a liquid is proportional to the partial pressure of that gas above the liquid. In mathematical terms, the concentration of dissolved gas, C, equals Henry's constant, kH, times the gas’s partial pressure, Pgas: C = kH Pgas. The constant kH depends on the specific gas–liquid pair and on temperature, so raising the partial pressure increases solubility linearly within the applicable range.

This principle is used to predict how gases dissolve in liquids, such as CO2 in water (carbonation), O2 in blood, or gases exchanged in environmental systems. It doesn’t apply to solids dissolving in water, and while temperature changes kH, the core relationship remains that solubility scales with the gas’s partial pressure above the liquid.