Question

Which of the following is used as a raw material for white washing walls?

• A. Quick lime
• B. Slaked lime
• C. Calcium carbonate
• D. Washing soda

Answer 1

The correct option is A Quick lime

A solution of $Ca(OH{)}_2$ (slaked lime) produced by the reaction of $CaO$ (quick lime) with water is used for white washing walls.
Calcium hydroxide reacts slowly with the carbon dioxide in air to form a thin layer of calcium carbonate on the walls.
$CaO\left(s\right)+H_{2}O\left(l\right)\to Ca\left(OH{)}_2\right(aq.)$
$Ca\left(OH{)}_2\right(aq.)+C{O}_2(g)\to CaC{O}_3(s)+H_{2}O(l)$