Question

C60-->CH4+CO3^2?

Give the complete balanced oxidation-reduction reaction occurring in acidic solution.

Answer 1

The given redox reaction in acidic medium is

C60 ------------> CH4 + CO₃^2-  

First of all we need to find the oxidation state of C in each of reactant and product.

Here oxidation state of C in C60 = 0

oxidation state of C in CH4 = - 4

oxidation state of C in CO₃^2-  = +4

Hence C60 is reduced to CH4 in which the oxidation state of C decreases from 0 to - 4 and oxidised to CO₃^2- in which the oxidation state of C increases from 0 to +4.

Now we can balance the redox reaction by balancing separately the oxidation - half and reduction - half reaction.

Oxidation - half reaction:

C60 -------------> CO₃^2-

To balance this reaction in acidic medium, we first need to balance C-atom and then we need to add 1 H2O molecule in opposite side for each excess oxygen atom and 2H⁺ on the same side. Finally the number of electrons need to be balanced on both sides.

Hence the oxidation half reaction reaction can be balanced as

C60 + 180H2O -------------> 60CO₃^2- + 360H⁺ + 240 e^- -------------- (1)

Reduction - half reaction:

C60 -------------> CH4

To balance this reaction in acidic medium, we first need to balance C-atom and then we need to add 1 H⁺  in opposite side for each excess H - atom. Finally the number of electrons need to be balanced on both sides.

Hence the reduction half reaction reaction can be balanced as

C60 + 240H⁺ + 240 e^- -------------> 60CH4 --------- (2)

Now adding reaction (1) and (2), the electrons on opposite side will cancel out and we get the final balanced equation as

2C60 + 180H2O --------------> 60CH4 + 60CO₃^2- + 120H⁺

or C60 + 90H2O --------------> 30CH4 + 30CO₃^2- + 60H⁺   (answer)

The above equation is the final balanced reaction in acidic medium