Question

Balance the following redox reaction in acidic solution. What are the coefficients in front of C2H4O in the balanced reaction? C2H4O(aq) + NnO4-(aq) → C2H4O2(aq) + MnO2(aq)

Answer 1

C in C2H4O has oxidation state of -1
C in C2H4O2 has oxidation state of 0
So, C in C2H4O is oxidised to C2H4O2

Mn in MnO4- has oxidation state of +7
Mn in MnO2 has oxidation state of +4
So, Mn in MnO4- is reduced to MnO2





Reduction half cell:
MnO4- + 3e- --> MnO2
Oxidation half cell:
C2H4O --> C2H4O2 + 1e-
Balance number of electrons to be same in both half reactions

Reduction half cell:
MnO4- + 3e- --> MnO2
Oxidation half cell:
3 C2H4O --> 3 C2H4O2 + 3e-

Lets combine both the reactions.
MnO4- + 3 C2H4O --> MnO2 + 3 C2H4O2
Balance Oxygen by adding water

MnO4- + 3 C2H4O + H2O --> MnO2 + 3 C2H4O2

Balance Hydrogen by adding H+
MnO4- + 3 C2H4O + H2O --> MnO2 + 3 C2H4O2 + 2 H+
This is balanced chemical equation in acidic medium

coefficient of C2H4O is 3

Answer: 3