The general equation for acid-metal reactions can be expressed as follows:

When an acid reacts with a metal, a salt and hydrogen gas are produced. This process is classified as a single displacement reaction, where the metal displaces the hydrogen ions from the acid, resulting in the formation of a salt. Hydrogen gas is subsequently released as a byproduct.

For example, when hydrochloric acid ($\text{HCl}$) reacts with magnesium ($\text{Mg}$), the products formed are magnesium chloride ($\text{MgCl}_2$), which is the salt, and hydrogen gas ($\text{H}_2$). The balanced chemical equation for this reaction can be represented as:

The type of salt produced depends on the specific acid and metal involved in the reaction. For instance, when sulfuric acid ($\text{H}_2\text{SO}_4$) reacts with zinc ($\text{Zn}$), the resulting products are zinc sulfate ($\text{ZnSO}_4$) and hydrogen gas ($\text{H}_2$). The balanced chemical equation for this reaction is:

It is essential to note that not all metals react with acids. The reactivity series of metals serves as a useful tool for predicting which metals will undergo reactions with acids. Metals that are positioned above hydrogen in the reactivity series will react with acids to generate a salt and hydrogen gas, whereas those situated below hydrogen will not react with acids.

In summary, the general equation for acid-metal reactions is a valuable framework for predicting the products of these reactions. This concept is fundamental in GCSE Chemistry, and a solid understanding of it will greatly assist you in your studies.