Assertion: A solution of slaked lime is used for whitewashing walls.
Reason: Calcium hydroxide reacts slowly with the carbon dioxide in air to form a thin layer of calcium carbonate on the walls.
Choose the correct option out of the following.
Answer & explanation
Correct answer: option 1
The correct answer is option 1. Both assertion and reason are correct, and reason is the correct explanation of assertion.
CaO(s) + H2O(l) → Ca(OH)2(aq) + Heat
Quick lime Slaked lime
A solution of slaked lime produced is used for whitewashing walls. Calcium hydroxide 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 whitewashing and gives a shiny finish to the walls. It is interesting to note that the chemical formula for marble is also CaCO3.
Ca(OH)2(aq) + CO2(g) → CaCO3(s) + H2O(l)