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Assertion (A): After white washing the walls, a shiny white finish on walls is obtained after two to three days.
Reason (R): Calcium oxide reacts with carbon dioxide to form calcium hydrogen carbonate which gives a shiny white finish.
Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:
(a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
(b) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
(c) Assertion (A) is true but reason (R) is false.
(d) Assertion (A) is false but reason (R) is true.
Answer
Calcium hydroxide is present in whitewash.
It reacts slowly with the carbon dioxide in air to form a thin layer of calcium carbonate on the walls.
Calcium carbonate is formed after two to three days of white washing. Hence the shiny white finish appears after two to three days on the walls.
Thus,
- Assertion is true
- Reasoning is false , as Calcium Carbonate is formed, not Calcium Hydrogen Carbonate
So, the correct
answer is (c)
