Question

A gas is liberated immediately with a brisk effervescence, when you add acetic acid to sodium hydrogen carbonate powder in a test tube. Name the gas and describe the test that confirms the identity of the gas. 

Answer 1

When acetic acid (CH₃COOH) is added to the sodium hydrogen carbonate (NaHCO₃) powder in a test tube, then the products obtained are sodium acetate, carbon dioxide and water.

Observations in this reaction are:
Brisk effervescence is seen because of CO₂ gas escaping out from the reaction mixture. The gas turns lime water milky that confirms the identity of CO₂ gas.

Chemical reactions involved:

CH₃COOH + NaHCO₃ →CH₃COONa + CO₂↑ + H₂O

Ca(OH)₂ + CO₂ → CaCO₃↓ + H₂O