Question

A substance X, which is an oxide of a group 2 element, is used intensively in the cement industry. This element is present in bones also. On treatment with water it forms a solution which turns red litmus blue. Identify X and also write the chemical reactions involved.

                                     OR
A substance X, which is an oxide of a metal is used intensively in the cement industry. This metal element is present in bones also. On treatment with water, it forms a solution which turns red litmus blue. Identify X and also write the equation for its chemical reaction with water.

Answer 1

The given substance X is calcium oxide. Calcium oxide is used intensively in the cement industry. The element present in it (which is present in bones also) is calcium. Calcium oxide on treatment with water forms a solution of calcium hydroxide [Ca(OH)₂] which is an alkali. Hence, it turns red litmus blue.