Looking at the name of an acid, how do you know if it only contains two elements or if it contains more than two?

Answer 1

If it contains only 2 elements it will begin with “hydro” as in

hydrochloric acid (HCl). If it contains more than 2 elements it is named based on the polyatomic (oxy) anion, as in nitric acid (HNO₃), nitrous acid (HNO₂), sulfuric acic (H₂SO₄).