(a) Burn a piece of charcoal. As the charcoal starts burning, transfer it into a gas jar/ glass tumbler. Cover the tumbler with a lid to ensure that the gas produced does not escape. Remove the charcoal piece after some time. Add a small quantity of water into the tumbler and quickly replace the lid. Shake the tumbler well. Check the solution with red and blue litmus papers. Saloni will find that the blue litmus paper turns red, that is the gas evolved is acidic in nature. (b) The gas evolved is carbon dioxide. Carbon dioxide + Water → Carbonic acid The carbonic acid turns blue litmus paper red.