Question

Why does water evaporate before its boiling point?

Answer 1

Explanation:

1. It is understood that evaporation and boiling both are different phenomena. Evaporation can be defined as the type of vaporization that occurs on a liquid's surface when it transitions from a liquid to a gas whereas boiling can be defined as the vaporization that occurs when a liquid is heated to its boiling point.
2. Boiling breaks intermolecular bonds in water rather than the bonds between hydrogen and oxygen atoms. This breaking of bonds can occur only at certain temperatures. Few molecules escape from the surface to the air during evaporation.
3. Evaporation is a process that occurs at the liquid's surface and can occur at any temperature, whereas boiling occurs under specific conditions and is a bulk transformation.
4. The boiling point of a liquid varies according to the applied pressure; the normal boiling point is the temperature at which the vapor pressure is equal to the standard sea-level atmospheric pressure (760 mm of mercury).

5. The water evaporates because of the heat in the water some molecules move quickly enough to escape into the air and evaporate.

6. Evaporation neither necessitates the use of additional energy nor necessitates the water reaching the boiling point.