What Is an Oxyacid in Chemistry?

Phosphoric acid diagram
Phosphoric acid is an oxyacid. Ben Mills/PD
by Anne Marie Helmenstine, Ph.D.
Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels.
Updated March 07, 2019

An oxyacid is an acid that contains an oxygen atom bonded to a hydrogen atom and at least one other element. An oxyacid dissociates in water to form the H+ cation and the anion of the acid. An oxyacid has the general structure X-O-H.

  • Also Known As: oxoacid
  • Examples: Sulfuric acid (H2SO4), phosphoric acid (H3PO4), and nitric acid (HNO3) are all oxyacids.

Note: Keto acids and oxocarboxylic acids are sometimes mistakenly called oxyacids.