A student adds a spoonful 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 chemical equation for the reaction.
Ethanoic acid or acetic acid is a carboxylic acid. When carboxylic acids are added to metal carbonates or bicarbonates, carbon dioxide gas is produced. The observations made are-
• A colourless odourless gas is produced which turns lime water milky. (Reason: as stated above, carbon dioxide gas is produced)
• Water droplets are also found in the walls of the flask. (Reason: as stated above water vapour is formed which condenses on the walls of the flask)
The reaction is as follows-
NaHCO3 +CH3COOH 
NaC2H3O2 + H2O + CO2