Naming Acids & Bases Cheat Sheet

Key Facts

• A binary acid has the general form $\mathrm{HX}$ and is named hydro + nonmetal root + ic acid, such as $\mathrm{HCl}$ as hydrochloric acid.
• An oxyacid has the general form $\mathrm{H_nXO_m}$ and is named from the oxyanion without using the prefix hydro.
• If the oxyanion ends in $\text{-ate}$, the acid name ends in $\text{-ic}$, such as $\mathrm{HNO_3}$ from nitrate as nitric acid.
• If the oxyanion ends in $\text{-ite}$, the acid name ends in $\text{-ous}$, such as $\mathrm{HNO_2}$ from nitrite as nitrous acid.
• A base containing hydroxide is usually named cation name + hydroxide, such as $\mathrm{NaOH}$ as sodium hydroxide.
• Transition metal bases need a Roman numeral for the metal charge, such as $\mathrm{Fe(OH)_3}$ as iron(III) hydroxide.
• The number of hydroxide ions in a base balances the cation charge, so $\mathrm{Ca^{2+}}$ pairs with $2$ hydroxides to form $\mathrm{Ca(OH)_2}$.
• Acid formulas are usually written with hydrogen first, while hydroxide base formulas usually place $\mathrm{OH}$ last.

Vocabulary

Acid

An acid is a compound that produces hydrogen ions, $\mathrm{H^+}$, in water.

Base

A base is a compound that produces hydroxide ions, $\mathrm{OH^-}$, in water or accepts hydrogen ions.

Binary Acid

A binary acid contains hydrogen and one other nonmetal element, such as $\mathrm{HBr}$.

Oxyacid

An oxyacid contains hydrogen, oxygen, and another element, usually as part of a polyatomic ion.

Oxyanion

An oxyanion is a negatively charged polyatomic ion containing oxygen, such as $\mathrm{NO_3^-}$ or $\mathrm{SO_4^{2-}}$.

Roman Numeral

A Roman numeral shows the charge of a transition metal ion in a compound name, such as iron(III) in $\mathrm{Fe(OH)_3}$.