In the compound KClO4 potassium perchlorate , the oxidation state of chlorine can be determined by considering the oxidation states of the other elements in the compound. Potassium K has an oxidation state of +1, and oxygen O has an oxidation state of -2. There are four oxygen atoms, so their total oxidation state is -8. The compound is neutral, so the sum of the oxidation states of all elements must be equal to zero. Therefore, the oxidation state of chlorine Cl can be calculated as follows: +1 + Cl oxidation state + -8 = 0 Cl oxidation state - 7 = 0The oxidation state of chlorine in KClO4 is +7.