How will you know that the reaction between hydrochloric acid and sodium bicarbonate is already complete?

The reaction between hydrochloric acid and sodium bicarbonate is complete when there are no more visible bubbles or fizzing, indicating that all the carbon dioxide gas produced has escaped. Additionally, if you use a pH indicator, the solution will show a neutral pH when the reaction is finished, as the acidic hydrochloric acid is neutralized by the basic sodium bicarbonate. Observing a clear solution without any solid residue of sodium bicarbonate also confirms completion.