When a piece of X is added to a sodium hydroxide solution, a gas Y is produced. Which of the following can be X and Y?

(a) X: Gold Y: Hydrogen
(b) X: Charcoal Y: Carbon dioxide
(c) X: Aluminium Y: Carbon dioxide
(d) X: Zinc Y: Hydrogen

Question 18

Explain the following:

(a) Lime water turns milky on passing carbon dioxide gas into it.
(b) Bubbles are produced when acetic acid is added to a solution of sodium hydrogen carbonate.

Write a balanced chemical equation for each of the following :

1. Carbon disulphide burns in air to give carbon dioxide and sulphur dioxide.

2. Calcium hydride reacts with water to form calcium hydroxide and hydrogen gas.

3. Methyl alcohol burns in air to form carbon dioxide and water.

4. Liquid hydrogen peroxide decomposes to give water and oxygen gas.

5. Aluminium hydroxide reacts with sulphuric acid to give ammonium sulphate and water.

6. Aluminium sulphate solution reacts with sodium hydroxide to form a precipitate of aluminium hydroxide.