# What type of compound forms hydrogen ions in solution?

An Arrhenius acid is defined as a substance that introduces ${H}^{+}$ ions in solution. There are other definitions of an acid that are broader than this, but one that specifically introduces ${H}^{+}$ in solution is called an Arrhenius acid.
Some examples are $H C l$, $H N {O}_{3}$, ${H}_{2} S {O}_{4}$, and $C {H}_{3} C O O H$