What is the oxidation number of manganese in the permanganate ion (mno4
a. 3
b. 2
c. 7
d. 2-

Each oxygen will have the oxidation number (2-), and we know the total charge is 1-. We have four oxygen atoms per molecule, so we can set up the equation:
(charge on Mn) + 4(charge on O) = -1
(charge on Mn) + 4(-2) = -1
(charge on Mn) - 8 = -1
Charge on Mn = 7
The answer is C. 7

i dont think thats what u call it but here

Explanation:

Water lowers the melting point of salt when it dissolves in it just as salt does for water!