# How does #"iodic acid"#, #HIO_3#, react with iodide anion, #I^-#, to give elemental iodine?

##### 2 Answers

This is a so-called

#### Explanation:

So

This is AFAIK balanced with respect to mass and charge, and therefore a reasonable representation of chemical reality.

**WARNING! Long answer!** The balanced equation is

#### Explanation:

We start with the unbalanced equation:

**Step 1. Identify the atoms that change oxidation number**

We start by determining the oxidation numbers of every atom in the equation.

We see that the oxidation number of

This is a **comproportionation** reaction, a reaction in which an element in a higher oxidation state reacts with the same element in a lower oxidation state to give the element in an intermediate oxidation state.

The changes in oxidation number are:

**Step 2. Equalize the changes in oxidation number**

We need 1 atom of

That also means that we need a total of 6

**Step 3. Insert coefficients to get these numbers**

**Step 4. Balance #"O"#**

We have fixed 3

Every formula now has a coefficient. The equation should be balanced.

**Step 7. Check that all atoms are balanced.**

The balanced equation is