Question

The boiling point of water can change due to different reasons. Pick the correct ones from below:

• A. It decreases with increase in pressure.
• B. It increases with increase in altitude.
• C. It increases on the addition of impurities.
• D. It decreases with an increase in altitude.

Answer 1

Answer: (C), (D)

The correct options are
C It increases on the addition of impurities.
D It decreases with an increase in altitude.

The boiling point of a liquid increases with an increase in atmospheric pressure and decreases with a decrease in pressure.
At high altitudes, the atmospheric pressure is less than $1\text{atm}$, hence, water boils at a temperature lower than ${100}^{\circ }\text{C}$ .
On the addition of impurities, the heat capacity of the water changes. The boiling point increases since a part of the supplied heat is used by the impurities.