What is produced when an acid reacts with a metal?

When an acid reacts with a metal, the primary products formed are a salt and hydrogen gas. This reaction is part of a category of chemical reactions where an acid can donate protons (H⁺ ions) and a metal typically displaces hydrogen from the acid.

The general reaction can be represented as follows:

Acid + Metal → Salt + Hydrogen gas

Here, the metal reacts with the anion from the acid to form the corresponding salt, while the hydrogen ions from the acid are reduced to form hydrogen gas. This is commonly observed in reactions involving acids like hydrochloric acid (HCl) with metals such as zinc (Zn) or magnesium (Mg).

In contrast, other option combinations like salt and oxygen, or salt and carbon dioxide, do not typically arise from the reaction between acids and metals. Similarly, salt and water are often products of reactions between acids and bases rather than acids and metals. Thus, understanding the specific types of reactions involved clarifies why the formation of salt and hydrogen is the correct outcome of this reaction.