Binary vs Ternary Acids: Key Differences & Examples
Binary acids are two-element acids—just hydrogen bonded to one non-metal (HCl, HBr). Ternary acids also contain hydrogen but add a third element: oxygen, forming polyatomic oxyanions (HNO₃, H₂SO₄).
People confuse them because both start with “H” and taste sour. The mix-up often happens in AP Chem homework, where one extra oxygen letter flips the naming rules and the acid’s strength.
Key Differences
Binary acids use the “hydro-ic” suffix (hydrochloric acid). Ternary acids change suffix with oxygen count: “-ous” for fewer oxygens (nitrous acid) and “-ic” for more (nitric acid).
Which One Should You Choose?
If your formula shows only H and a halogen, call it binary. If you spot oxygen in the formula, switch to ternary naming rules—always check the oxyanion’s charge.
Examples and Daily Life
HCl in your stomach? Binary. Citric acid in lemons? Ternary. Labeling lab bottles correctly avoids dangerous mix-ups between cleaning agents and food-grade acids.
Is stomach acid binary or ternary?
Stomach acid is primarily HCl, so it’s binary.
Why does citric acid have three elements but isn’t called ternary?
It is ternary; the everyday name just hides the chemistry jargon.