If we replace the hydrogen with a metal, what happens is that a salt will be formed and the hydrogen will be liberated. The reaction that takes place is as follows: Acid + metal → salt + hydrogen

It should however be noted that to replace hydrogen with metal, the metal should be highly reactive. Reactive metals are those that have a greater tendency to lose electrons and form positive ions. Reactivity is a relative attribute. The more reactive elements are placed higher on the reactivity table while those that are less reactive are lower on the table.

The higher the metal is on the reactivity table the greater its ability to replace hydrogen. Examples of reactive metals that can replace hydrogen in an acid are magnesium and zinc. The reaction that takes place between magnesium and sulfuric acid is : Magnesium + sulfuric acid → magnesium sulphate + hydrogen