Henry’s Law describes the relationship between the solubility of a gas in a liquid and the pressure of that gas above the liquid.
Statement of Henry’s Law:
At a constant temperature, the amount of gas that dissolves in a given volume of liquid is directly proportional to the partial pressure of the gas above the liquid.
In simple words, the higher the pressure of the gas above the liquid, the more gas molecules get “pushed” into the liquid, increasing its solubility.
Key Points:
- It applies mainly to gases dissolved in liquids.
- The law is important in understanding carbonated drinks, scuba diving, and respiration in blood.
- At higher pressures, more gas dissolves; at lower pressures, gas escapes from the solution.
Everyday Examples:
- Soda bottles – Carbon dioxide is dissolved in soda under high pressure. When opened, pressure drops, and the gas escapes as bubbles.
- Scuba diving – At high water pressure, more nitrogen dissolves in a diver’s blood. If they rise too quickly, nitrogen comes out as bubbles (causing decompression sickness or “the bends”).
- Aquatic life – Oxygen dissolves in water from the air, allowing fish and other organisms to breathe.