A substance that combines with hydrogen ions (H+) is called a base.

Here's why:

* Bases are substances that can accept hydrogen ions (protons) in solution. They are also known as alkalines.

* Acids, on the other hand, are substances that donate hydrogen ions (protons) in solution.

The combination of a base and an acid results in a neutralization reaction, where the hydrogen ions from the acid react with the base, forming water (H2O) and a salt.

Example:

Sodium hydroxide (NaOH) is a strong base. When it reacts with hydrochloric acid (HCl), the following reaction occurs:

NaOH + HCl → NaCl + H2O

Here, the hydroxide ion (OH-) from NaOH accepts a hydrogen ion (H+) from HCl, forming water. The remaining ions, Na+ and Cl-, form sodium chloride (NaCl).