Here's why:

* Acids release hydrogen ions (H+) in solution.

* Bases release hydroxide ions (OH-) in solution.

* When an acid and base react, the hydrogen ions and hydroxide ions combine to form water (H2O), a neutral substance. This process is called neutralization.

For example, when you mix a strong acid like hydrochloric acid (HCl) with a strong base like sodium hydroxide (NaOH), the following reaction occurs:

HCl + NaOH → NaCl + H2O

This results in the formation of salt (NaCl) and water, which are both neutral substances.