MP Board · Class 12 · Chemistry · SolutionsState Henry's law and discuss its important applications. Also, explain the effect of temperature on the solubility of gases in liquids with reasons.

Henry's Law\nHenry's law states that at a constant temperature, the solubility of a gas in a liquid is directly proportional to the partial pressure of the gas present above the surface of the liquid or solution. Mathematically, it is expressed as $p = K_H \cdot x$, where $p$ is the partial pressure of the gas in the vapour phase, $x$ is the mole fraction of the gas in the solution, and $K_H$ is Henry's law constant.

Important Applications of Henry's Law

1. Production of Carbonated Beverages: To increase the solubility of carbon dioxide in soft drinks and soda water, the bottles are sealed under high pressure.
2. Scuba Diving: Deep sea divers breathe compressed air at high pressures. As the divers breathe air under high pressure, greater amounts of nitrogen gas dissolve in blood. When the diver ascends towards the surface, pressure decreases, leading to the release of dissolved nitrogen gas and the formation of bubbles in the blood. This condition is known as 'bends', which is painful and dangerous. To avoid bends and toxic effects of high concentrations of nitrogen, scuba divers' tanks are diluted with helium (11.6%), nitrogen (56.2%), and oxygen (32.2%).
3. Climbing High Altitudes: At high altitudes, the partial pressure of oxygen is low than at the ground level. This results in low concentrations of oxygen in the blood and tissues of people living or climbing high altitudes, causing climbers to become weak and unable to think clearly, a condition known as anoxia.

Effect of Temperature on Solubility\nSolubility of gases in liquids decreases with an increase in temperature. Dissolution of a gas in a liquid is an exothermic process (heat is released). According to Le Chatelier's principle, when temperature is increased, the equilibrium shifts in the backward direction, thereby decreasing the solubility of the gas.