When you add sodium hydrogen carbonate to acetic acid in a test tube, a gas liberates immediately with brisk effervescence. Name this gas. Describe the method of testing this gas.

When acetic acid reacts with sodium hydrogen carbonate, CO2 is released with brisk effervescence. The presence of CO2 can be checked by passing the gas through lime water which turns milky on reacting with CO2 thus indicating its presence. NaHCO3 + CH3COOH → CH3COONa + H2O + CO2