Acids are molecular compounds that release hydrogen ions (H⁺) when dissolved in water. They play an important role not only in chemistry but also in our daily lives. For example, hydrochloric acid is used in the stomach for digestion, while sulfuric acid is found in car batteries and cleaning agents. ^[1-4]

All acids contain hydrogen. The names of acids depend on the type of anion (negative ion) they contain. These anions can either be monatomic (containing one atom) or polyatomic (containing more than one atom).

Why Naming Acids Matters

Naming acids the right way helps everyone understand what is in them and how they react. It makes writing chemical equations easier and helps avoid mistakes, especially when working with strong or dangerous acids. ^[3,4]

Although we can group acids in various ways, we primarily classify them as binary acids and oxyacids for naming purposes.

1. Binary Acids

Binary acids are compounds consisting of hydrogen and a single nonmetal element, typically a halogen. Their general formula is HX, where X is a monoatomic, nonmetal anion ending in “-ide”.

Naming Rules

• Identify the nonmetal anion
• Use the root of the nonmetal’s name
• Add the suffix “-ic”
• Add the prefix “hydro” and end with the word “acid”

General Format

hydro + nonmetal root + -ic + acid = acid name

Examples

Let us take an example and apply it to the above format.

HCl

• The nonmetal anion is Cl^– or chloride
• The root of nonmetal’s name is “chlor”
• Add “ic” to “chlor”
• Add the prefix “hydro” and end with “acid”

 hydro + chlor + -ic + acid = hydrochloric acid

The table below summarizes the names of common binary acids.

2. Oxyacids

Unlike binary acids, oxyacids contain hydrogen, a central nonmetal, and oxygen. Their names are based on the polyatomic ions they contain. Their general formula is H_xA_yO_z, where A is a central nonmetal element. 

Naming Rules

• Identify the polyatomic ion
• If the ion ends in “-ate”, change the suffix to “-ic”
• If the ion ends in “-ite”, change the suffix to “-ous”
• Add the word “acid”
• Do not use the prefix “hydro-” for oxyacids

Examples

Let us take a couple of examples and apply the above rules.

Ex. 1: HNO₃

• The polyatomic anion is NO₃^– or nitrate
• Since the anion ends in “-ate”, change the suffix to “-ic”: nitrate → nitric
• Add the word “acid”

nitric + acid = nitric acid

Ex. 2: H₂SO₃

• The polyatomic anion is SO₃^2- or sulfite
• Since the anion ends in “-ite”, change the suffix to “-ous”: sulfite → sulfurous
• Add the word “acid”

sulfurous + acid = sulfurous acid

Here is a table of all the names of oxyacids.

Mastering acid nomenclature not only helps students connect chemical names with formulas but also strengthens their understanding of ionic bonding, polyatomic ions, and the structure of covalent compounds. It lays a foundation for predicting reactivity and writing correct chemical equations.