MnO4(aq) + 8H + 5Fe2+ \(\to\) Mn2+(aq) + 5Fe3+(aq) + H2O. The oxidation number of maganese in the above reaction changed from
-
+7 to +2
- +6 to +2
- +5 to +2
- +4 to +2
The correct answer is: A
Explanation
\(MnO_{{4}{(aq)}}\) has a charge of \(-1\)
Let the oxidation number of \(Mn\) in \(MnO_{{4}{(aq)}}\) be X
Recall, the oxidation number of \(O_{2}\) is \(-2\)
\(\therefore\) \(X + (-2\times 4) = -1\)
\(X - 8 = -1\)
\(X = +7\)