GENERAL KNOWLEDGE

Detailed explanation-1: -Boiling point is the temperature at which the vapor pressure becomes equal to atmospheric pressure. It is a characteristic property of liquids and is a criterion to check the purity of liquid. As the external pressure increases, the boiling point increases.

Detailed explanation-2: -At the point where the vapor pressure is equal to the atmospheric pressure boiling will begin. In effect, without any external pressure the liquid molecules will be able to spread out and change from a liquid to a gaseous phase.

Detailed explanation-3: -As the gas bubble forms within the liquid, the vapour pressure within the bubble must be equal to atmospheric pressure to escape the surface, at which point the liquid boils.

Detailed explanation-4: -At the normal boiling point of 100 °C, it equals the standard atmospheric pressure of 760 Torr or 101.325 kPa.

Detailed explanation-5: -For a liquid to boil the pressure of gas above the liquid must equal the vapor pressure and bubbles will form in the liquid. Hence water boils at 100 °C when the pressure is 1 atm (101.3 kPa).