What gives a shiny finish to walls a few days after whitewashing?
Question
What gives a shiny finish to walls a few days after whitewashing?
Calcium oxide formed on the surface
Calcium carbonate formed by reaction with carbon dioxide in air
Evaporation of water alone
Sunlight bleaching the wall
Answer
Calcium carbonate formed by reaction with carbon dioxide in air
Detailed Explanation
Calcium hydroxide slowly reacts with carbon dioxide in the air to form a thin layer of calcium carbonate, which gives the shiny finish. — Examisthan.com