Question

a student dropped few pieces of marble in dilute hydrochloric acid contained in a test tube. the evolved gas was then passed through lime water. what change would be observed lime water? what will happen if excess of gas is passed through lime water. with the help of balanced chemical equation for the changes observed explain the observations ​

Answer 1

When dilute HCl is added to marble which is calcium carbonate, it forms calcium chloride, water and carbon dioxide. The chemical equation for the reaction is as follows: CaCO3 + 2HCl → CaCl2 + H2O + CO2

Carbon dioxide gas turns lime water milky due to the formation of calcium carbonate.

The chemical equation showing the reaction between lime water and carbon dioxide is as follows: Ca(OH)2 + CO2 → CaCO3 + H2O