Question

Which of the following sets of oxidation numbers is NOT correct? KMnO4 : K +2, Mn +6, O -2 NaCHO2 : Na +1, C +2, H +1, O -2 Zn(OH)2 : Zn +2, O -2, H +1 SCl2 : S +2, Cl -1

Answer 1

KMnO4 has the incorrect set of oxidation numbers. Whenever there is an alkali metal, it has an oxidation number of +1. As you can see, K is said to have an oxidation number of +2, so it is incorrect.