In the reaction between a crushed antacid tablet and vinegar what gas is emitted

The answer is: emitted gas is carbon dioxide (CO₂).

Neutralization is is reaction in which an acid (in this example vinegar or acetic acid CH₃COOH) and a base (in this example soda)

Balanced chemical reaction of vinegar and antacid:

CH₃COOH (aq) + NaHCO₃ (aq) → CH₃COONa (aq) + H₂O (l) + CO₂ (g).

Sodium acetate (CH₃COONa) is a salt.

Sodium bicarbonate (NaHCO₃) is an antacid. Sodium bicarbonate is the active ingredient in baking soda.