# What is a generalization for determining whether an acid name will end in the suffix -ie or -ous?

Mar 13, 2017

The use of $\text{hypo}$, $\text{per}$, prefixes, and $\text{ous}$ and $\text{ic}$ endings to describe acids, their salts, and oxidation states is a bit old-fashioned..........

#### Explanation:

We can look at the oxyacids of chlorine, and assign an oxidation to chlorine:

$H O C l , \text{hypochlorous acid} , C l \left(+ I\right)$;

$H O C l \left(= O\right) , \text{chlorous acid} , C l \left(+ I I I\right)$;

$H O C l {\left(= O\right)}_{2} , \text{chloric acid} , C l \left(+ V\right)$;

$H O C l {\left(= O\right)}_{3} , \text{perchloric acid} , C l \left(+ V I I\right)$.

And in general, the acid/salt with the LOWER oxidation state has an $\text{ous}$ ending; and the acid/salt with the HIGHER oxidation state has an $\text{ic}$ ending.

The use of $\text{hypo}$ means $\text{reduced}$, here with respect to oxidation state; $\text{per}$ means $\text{maximum}$. These are all old-fashioned names, and depending on your syllabus, you should not have to master them. You would, however, be required to find the oxidation state of chlorine in the oxoacid.