1) Metals: When certain metals such as iron or zinc react with hydrochloric acid, they undergo a chemical reaction known as a metal-acid reaction. This reaction results in the formation of a metal chloride salt and releases hydrogen gas. For example:

Fe + 2HCl -> FeCl2 + H2

2) Metal Carbonates: Metal carbonates, such as sodium carbonate (Na2CO3) or calcium carbonate (CaCO3), can react with hydrochloric acid to produce a salt, carbon dioxide gas, and water. The general reaction can be represented as:

Metal Carbonate + Hydrochloric Acid -> Metal Chloride + Carbon Dioxide + Water

For example:

Na2CO3 + 2HCl -> 2NaCl + CO2 + H2O