In the compound HNO3 nitric acid , the oxidation state of nitrogen can be determined using the oxidation states of hydrogen and oxygen and the overall charge of the compound.In HNO3, hydrogen has an oxidation state of +1, and oxygen has an oxidation state of -2. The compound is neutral, so the sum of the oxidation states of all the atoms must equal zero.Let x be the oxidation state of nitrogen. The equation for the sum of the oxidation states is: +1 + x + 3 -2 = 0Solving for x:1 + x - 6 = 0x - 5 = 0x = +5So, the oxidation state of nitrogen in HNO3 is +5.