In order for efflorescence to form, which of the following conditions must exist? i. Soluble salts must be present. ii. Salts must be dissolved by a liquid. iii. The liquid must have a path to migrate to the surface and evaporate.
- AOnly (i)
- BOnly (i) and (ii)
- COnly (ii) and (iii)
- D(i), (ii) and (iii)Correct
Solution
Concept
Essential conditions for efflorescence formation
Formula
NONE
Step-by-step solution
1. Efflorescence occurs when soluble salts migrate to the building material surface through moisture movement. 3. Therefore, only (ii) and (iii) are selected. Answer: D
Explanation
Efflorescence requires soluble salts within the material, moisture to dissolve those salts, and a continuous path for the solution to migrate to the surface where water can evaporate. If any of these three factors is absent, efflorescence cannot occur. Because all three listed conditions are essential, option D is the correct answer.
Why the other options are wrong
A) Statement (i) alone is insufficient because moisture and a drainage path are also required. B) Statements (i) and (ii) omit the necessity of a migration path to the surface.
Shortcut
Efflorescence needs 3 things: soluble salts + water/liquid + a pathway to migrate and evaporate.
Common mistake
Selecting option B by overlooking that a migration and evaporation path for liquid is necessary for efflorescence to occur.
Correct answer: D) (i), (ii) and (iii)