State Henry's law and mention some important applications.

Explanation

Applications : 1. To increase the solubility of `CO_2` in soft drinks, the bottle is sealed under high pressure. 2. The partial pressure of oxygen at high altitudes is smaller than at the sea level. This results in low concentration of oxygen in the blood and tissues. Low blood oxygen causes climbers to become weak and unable to think. Such symptoms are known as anoxia. 3. Scuba divers face the problems of high concentration of dissolved gases while breathing air at high pressure underwater. When the divers reach the surface, the pressure gradually decreases. This releases the dissolved gases and leads to the formation of bubbles of nitrogen in blood. This blocks capillaries and creates a medical condition known as bends which are painful and dangerous to life. To avoid bends, tanks used by scuba divers are filled with air diluted with helium (11.7% helium, 56.2% nitrogen and 32.1% oxygen)