Question

The change in state from solid to gas is known as:

• A. melting
• B. boiling
• C. freezing
• D. sublimation

Answer 1

The correct option is D

sublimation

Explanation of correct option:

Option (D):

1. Sublimation: The change of state of a substance in which a solid directly changes into the gaseous state is known as sublimation.
2. In sublimation, the particles of a substance move from being a very tightly packed solid to a very loosely packed gaseous state.

Explanation of incorrect option:

Option (A):

1. Melting: The change of state from solid to liquid is known as melting.
2. The temperature at which a substance melts is known as the melting point of that substance.

Option (B):

1. Boiling: On applying heat to a liquid, after some time, its molecules become energetic and start escaping from the surface of the liquid.
2. This is the start of the process of boiling and the liquid starts converting into gas. This change in the state of liquid at a fixed temperature is known as boiling.

Option (C):

1. Freezing: The change in the state of a substance from liquid to solid is known as freezing.
2. For example, water freezes at 0^o C.

Hence, the correct option is (D).