Question

Question #68906

Answer 1

oxidation

Explanation:

Let the oxidation state of Manganese be `x`

In `MnO2`:

`x + 2(-2)=0`
`x=4`

In `MnO4^-`:

`x+4(-2)=-1`
`x=7`

Hence, `MnO2` is oxidised, as the oxidation state of Manganese increases from `+4` in `MnO2` to `+7` in `MnO4^-`, therefore it is an oxidation reaction.

OR

Oxidation, as each mole of `MnO2` gains 2 moles of oxygen atoms to form `MnO4^-`.