Question

The process of changing water vapour into water is called:
(A) Boiling
(B) Evaporation
(C) Melting
(D) Condensation

Answer 1

Hint: We know water exists in all the three states i.e. solid, liquid, gas. The interconversion of matter is visible in normal day to life. It depends on the temperature of water in all the three states.

Complete step by step solution:
Matter can exist in either of three main states: solid, liquid, or gas.
Solid matter is composed of tightly packed particles, that means solid will retain its shape. The particles in solids are not free to move around.
Liquid matter is made of more loosely packed particles than solids. It will take the shape of its container. Particles can move about within a liquid, but they are packed densely enough that volume is maintained.
Gaseous matter is composed of particles packed so loosely that it has neither a definite shape nor a definite volume.
Now let’s take a look at our options.

A. The process by which the vapour pressure of a liquid becomes equal to the atmospheric pressure is called boiling.
B. A liquid can be converted to a gas through heating at constant pressure to the substance’s boiling point. This process of a liquid changing to a gas is called evaporation.
C. The process by which a substance changes from the solid phase to the liquid phase is called melting.
D. The process of changing water vapour, which is in gaseous form, into water, which is liquid form, is called condensation.

So, the correct option is (d).

Note: When thermal energy is added to a substance the temperature of the substance increases, which can change its state from solid to liquid, liquid to gas, or solid to gas. When energy is removed, the opposite happens, decreasing the substance’s temperature and turning it from liquid to solid, gas to solid, or from gas to liquid.