With increase in impurities, the boiling point of water

Solution

Boiling point of water is defined as the temperature at which the vapour pressure becomes equal to the atmospheric pressure. Adding impurities to a solution, in most cases, increases the boiling point of the solution. This occurs because the presence of impurities decreases the number of water molecules available to become vaporized during boiling. Hence, the vapour pressure becomes equal to the atmospheric pressure at a higher temperature. Thus, impurities increase the boiling point of water. Hence, option A is correct.