How to find the oxidation state of elements in acids.

Let’s take the acid H2SO4 – sulfuric acid. The oxidation state of hydrogen (H) is constant +1 and the oxidation state of oxygen (O) is constant -2. Sulfur (S) is unknown, let it be x. The oxidation state of hydrogen is multiplied by the index, that is, +1 x 2 = +2. Now we multiply the oxidation state of oxygen by the index -2 x 4 = -8. In total, the connection must be neutral, that is, equal to 0, to level it is necessary to add 6 to +2, this is equal to +8. +8 and -8 are neutral, so sulfur is +6.

So it is with the rest of the acids. HNO3 is nitric acid. Hydrogen +1, oxygen -2 x 3 = -6, respectively nitrogen +5.