2.4 Naming Acids

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In this lesson you will learn:

-How to name Binary Acids

-How to name Oxoacids (a.k.a Oxyacids)

How to Name Binary Acids

A binary acid generally contains hydrogen and one other element such as HCl or H2S (HCN is considered a binary acid too).


The names for binary acids all follow the same pattern:

hydro-element-ic acid

The only variance is the use of the root of the particular element. 


Here are the names of some common binary acids:

HCl     hydrochloric acid

H2S    hydrosulfuric acid

HI       hydroiodic acid

How to Name Oxoacids

Oxoacids (a.k.a oxyacids) are the acids of the polyatomic oxoanions.  These include the following:

H2SO4 is the oxoacid of the sulfate ion, SO42-

H2SO3 is the oxoacid of the sulfite ion SO32-

HNO3 is the oxoacid of the nitrate ion NO3-

HNO2 is the oxoacid of the nitrite ion, NO2-


To name the corresponding oxoacid, replace the -ic suffix with -ate or the -ite suffix with -ous and then add the word acid:

H2SO4     sulfuric acid

H2SO3     sulfurous acid

HNO3       nitric acid

HNO2       nitrous acid


For Cl, Br, and I there are four oxoanions and therefore four corresponding oxoacids.  But the same procedure of replacing the suffixes is used so as long as you know the name of the oxoanion you should be able to name the corresponding oxoacid:

ClO4- perchlorate HClO4 perchloric acid
ClO3- chlorate HClO3 chloric acid
ClO2- perchlorite HClO2 chlorous acid
ClO- hypochlorite HClO hypochlorous acid

Naming Acids Practice


hydrobromic acid


hydrosulfuric acid

hydroselenic acid


hydrofluoric acid



phosphoric acid


bromous acid

carbonic acid


hypoiodous acid

HIO (or HOI)

Naming Ionic or Molecular Compounds?