A student adds a spoon full of powdered sodium hydrogen carbonate to a flask containing ethanoic acid. List two main observations he must note in his notebook about the reaction that takes place. Also write the chemical equation for the reaction.

When acetic acid is added to NaHCO₃ solution, carbon dioxide gas with brisk effervescence is evolved from the flask.
CH₃COOH + NaHCO₃ → CH₃COONa + CO₂ + H₂O
So, the observations are:

1. Evolution of carbon dioxide gas with brisk effervescence.
2. Colorless gas is evolved with generation of heat.