Question #68906

1 Answer
Oct 17, 2017

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^-#.