Question

A substance is said to be in the liquid state if under normal pressure its

• A. melting point is above the room temperature.
• B. boiling point is below the room temperature.
• C. melting point is below the room temperature.
• D. boiling point is above the room temperature.

Answer 1

The correct option is C

melting point is below the room temperature.

Explanation for the correct option:

(c) melting point is below the room temperature

1. Melting point is the temperature at which a liquid start to melt.
2. If melting point of a substance is below the room temperature. Then it will be converted into liquid state before the room temperature.
3. So, the substance will exist in liquid form at room temperature.

Explanation for the incorrect options:

(a) melting point is above the room temperature

1. If melting point of a substance is above the room temperature. Then it will not be converted into liquid state at the room temperature.
2. So, the substance will exist in solid form at room temperature.

(b) boiling point is below the room temperature

1. If boiling point of a substance is below the room temperature. Then it will be converted into gaseous state before the room temperature.
2. So, the substance will exist in gaseous form at room temperature.

(d) boiling point is above the room temperature

1. If boiling point of a substance is above the room temperature. We can not say that the substance will be in liquid form at room temperature.
2. If a substance is in solid form at room temperature, then also its boiling point will be above the room temperature.

Hence, option (c) is correct. A substance is said to be in the liquid state if under normal pressure its melting point is below the room temperature.