Question

Metal.

Hint:

Acid-base reactions always produce salt and water. Acids reacting with metals or carbonates can also produce hydrogen gas or carbon dioxide.

Answer 1

When an acid reacts with a metal, a salt and hydrogen gas are produced. For example, when zinc (Zn) reacts with hydrochloric acid (HCl), zinc chloride (ZnCl₂) and hydrogen gas (H₂) are formed. The chemical equation is: \[ Zn (s) + 2HCl (aq) \rightarrow ZnCl_2 (aq) + H_2 (g) \]