Question

work out the oxidation number of underline element MnO-4​

Answer 1

Answer:

Sum of all the oxidation numbers in a polyatomic ion is equal to the charge on the ion. Thus, the total charge on the polyatomic anion is −1. Thus, the oxidation number of Mn in MnO−4 is +7.

Explanation:

Let oxidation number of Mn be x.

We know that, Ox. no. of O=−2.

So, Ox. no. Mn+ 4(Ox. no. O)=−1

x+4(−2)=−1

or x−8=−1

or x=+8−1=+7

The oxidation number of Mn in [MnO4]− ion is +7.