State Henry's law and mention some important applications.
Henry'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 x, where p is the partial pressure of the gas in vapour phase, x is the mole fraction of the gas in solution, and K_H is Henry's law constant.
Important applications include: (i) To increase the solubility of CO_2 in soft drinks and soda water, the bottle is sealed under high pressure. (ii) Scuba divers breathing air at high pressure underwater have increased solubility of atmospheric gases in blood. When they come towards the surface, pressure decreases, releasing dissolved gases and forming bubbles of nitrogen in blood, which blocks capillaries and creates a painful medical condition called bends.
Explanation
The answer correctly states Henry's law from the NCERT textbook, including both the qualitative statement and the mathematical expression p = K_H x. The two applications are directly sourced from the textbook context - the CO_2 solubility in soft drinks and the scuba diver/bends phenomenon. The answer uses bold formatting for key terms and fits within the 80-120 word limit for a 2-mark question.