Building Construction MCQ with answer and solution

Concept

Deliquescence is when a material absorbs moisture from air until it dissolves and becomes a liquid solution.

Step-by-step solution

1. The material must absorb moisture from air AND dissolve into a liquid. 2. Hygroscopicity means only absorbing moisture from air; the material stays solid. 3. Absorbing so much moisture that the material dissolves is called deliquescence. 4. So the answer is (A).

Explanation

Some materials, like calcium chloride, absorb so much water vapour from air that they dissolve and form a liquid. This property is called deliquescence. Hygroscopic materials also absorb moisture but they do not turn into liquid.

Why the other options are wrong

(B) Hygroscopicity is absorbing moisture from air without dissolving. (C) Wilting is the drooping of plants due to lack of water (soil-plant term). (D) Capillarity is the rise or movement of water through fine pores or tubes.

Shortcut

Deliquescence means it becomes liquid; hygroscopic means it only becomes moist.

Common mistake

Choosing hygroscopicity, because it also involves absorbing moisture from air, and ignoring the word 'dissolve'.