Which gas is produced during the reaction of an acid with a metal?

• When metals react with an acid, hydrogen gas is typically produced. 
• This is because the acid donates a hydrogen ion (H⁺) to the metal, which then reacts with another hydrogen ion to form hydrogen gas (H₂). The metal combines with the remaining anion from the acid to form a salt.
• For example, when zinc (Zn) reacts with hydrochloric acid (HCl), the following reaction occurs:

                 Zn + 2HCl → ZnCl₂ + H₂

• In this reaction, zinc combines with the chloride anion from hydrochloric acid to form zinc chloride, and hydrogen gas is produced.