What gas does sodium bicarbonate and hydrochloric acid make?

Carbon Dioxide

NaHCO3(aq) + HCl(aq) --> NaCl(aq) + H2O(l) + CO2(g)

Sodium bicarbonate (aqueous) reacts with hydrochloric acid (aqueous) to form sodium chloride (aqueous), liquid water, and gaseous carbon dioxide.