Question

What is the oxidation state of phosphorus in HPO3?

Answer 1

+3

Explanation:

Phophite (`PO_3^(3-)`) has a charge of -3, so I'm going to guess you meant to ask what the oxidation state of P was in `H_3PO_3`

In `H_3PO_3` the oxygens will always have a -2 charge and hydrogen is +1.

So the total positive charge from Hydrogen is +3 (+1 x 3)
The total negative charge from Oxygen is -6 (-2 x 3)

The compound is electrically neutral, so the phosphorus must have an oxidation state of +3.

3H = +1 x 3 = +3
1P = +3 x 1 = +3
3O = -2 x 3 = -6

Total charge = 0

Hope this helps!