Question

The vapour pressure of a deliquescent substance is:

• A. equal to the atmospheric pressure
• B. equal to that of the water vapour in air
• C. greater than that of the water vapour in air
• D. less than that of the water vapour in air

Answer 1

The correct option is D less than that of the water vapour in air

Deliquescence is a process by which a substance absorbs moisture from the atmosphere until it dissolves in the absorbed water & forms a solution.

Deliquescence occurs when the vapour pressure of the solution that is formed is less than the partial pressure of water in the air.

All soluble salts will deliquesce if the air is sufficiently humid.

Hence, the correct option is $\text{D}$