Question

It takes much longer time to boil off a certain quantity of water rather than to bring it to its boiling point from the room tempertatere of 25 degree celcius. Give reason

Answer 1

Boiling point is the temperature at which a liquid starts boiling or begins to change its phase from liquid to vapor. So, a certain amount of heat is required to bring a liquid to its boiling point.

However, to change the phase of the liquid to vapor at this temperature, extra heat is required. This extra heat breaks the molecular bonds between the molecules of the liquid and change it to vapor state.

So, when you put a bowl of liquid above a heater it takes more time to boil off the liquid than to just bring the liquid to its boiling point.