Dheeraj observed that the colour of walls of his house changes gradually into shiny white after white wash. He asked you, why did the colour changed into bright white.
Predict the reason.

Explanation

1) Slaked lime is prepared by adding water to quick lime.
2) `CaO+H_(2)O rarr Ca(OH)_(2)+Q`
3) `Ca(OH)_(2)` is called slaked lime. It uses in while washing.
4) After applying white wash on the walls of a house, first no colour is observed.
5) But after sometime shiny white finish will be observed.
6) Because, calcium hydroxide reacts with slowly with the carbon dioxide in air 10 form a thick layer of calcium carbonate on the walls. It gives a shiny finish to the walls.
7) `Ca(OH)_(2)+CO_(2)rarr CaCO_(3)+H_(2)O`
8) The chemical formula of marble is `CaCO_(3)`.