Question

A student dropped few piecesof marble in dilute HClcontained in a test tube. The gas evolvedwas passed through lime water. What change would be observed in lime water? Write chemical reactions for both the changes observed.

Answer 1

When the few pieces of marble is reacted with dil HCl and the gas evolved is passed through lime water, the solution turns milky thus confirming the presence of carbonate. The chemical equation is as follows:

CaCO3 (marble is recrystallised calcite, a polymorph of calcium carbonate) + HCl -> CaCl2 + CO2 (turns lime water milky) + H2O