57. With reference to relationship between pressure and boiling point, which among the
following statements is/are correct?
1. Boiling point of water decreases with increase in atmospheric pressure.
2.The boiling point of water decreases in pressure cookers.
Any liquid boils at that temperature at which its vapour pressure equals that of the atmospheric pressure. At the ground level, water boils at 100 degrees C at normal atmospheric pressure. At very high altitudes,the atmosphere thins and the pressure will be less, so that water boils at a temperature below 100 degrees C. This makes it difficult to cook in open pans in hilly regions, and we have to use a pressure cooker.
In the pressure cooker the pressure inside the container will be 2-3 times higher than at ground level.
Hence water will boil at around 120 degrees C, and the materials get cooked completely. Thus one can observe a fall in boiling points of water and other liquids at hills due to the fall in the atmospheric pressure