Acid - Wikipedia
2019-6-19 · An acid is a molecule or ion capable of donating a proton (hydrogen ion H+), or, alternatively, capable of forming a covalent bond with an electron pair (a Lewis acid).[1] The first category of acids is the proton donors or Brønsted–Lowry acids. In the special case of aqueous solutions, proton donors form the hydronium ion H3O+ and are ...