Question

Question #f5981

Answer 1

The oxidation number of `Mn` in `MnCl_2` is +2 while its oxidation number in `MnO_2` is +4.

Explanation:

With a few exceptions, the oxidation number of an element is equal to its charge. In `MnCl_2`, the charge/oxidation number of the `Cl` atom is -1 since it is in the halogen family, and since the molecule `MnCl_2` has 2 `Cl` atoms, it has a -2 oxidation number. Assuming your compound is a neutral compound with no overall charge, `Mn` would have a +2 oxidation number in the compound.

For `MnO_2`, `O` has a -2 charge/oxidation number, so 2 `O` atoms would have a charge of -4. This means `Mn` has an oxidation number of +4 in order to make the neutral compound.