Write the reaction in two half reactions,oxidation half and reduction half as:
Oxidation:
Fe(CN)4−6→Fe3++CO2+NO−3Reduction:MnO−4→Mn2+
Balance all other atoms except O and H.
Fe(CN)4−6→Fe3++6CO2+6NO−3
MnO−4→Mn2+
Now balance the oxygen atoms by adding H2O molecules.
Fe(CN)4−6+30H2O→Fe3++6CO2+6NO−3
MnO−4→Mn2++4H2O
Now balance hydrogen atoms by adding H+ ions.
Fe(CN)4−6+30H2O→Fe3++6CO2+6NO−3+60H+
MnO−4+8H+→Mn2++4H2O
To balance the charge,add electrons to more positive side to equal the less positive side of the half reaction.
Fe(CN)4−6+30H2O→Fe3++6CO2+6NO−3+60H++61e−
MnO−4+8H++5e−→Mn2++4H2O
Now multiply oxidation half reaction by 5 and reduction half reaction by 61 and add both the reactions we will get
5Fe(CN)4−6+61MnO−4+188H+→5Fe3++30CO2+30NO−3+94H2O+61Mn2+