CN^-1 + MnO4 ^-1 = CNO-1 + MnO2 (basic) Solution Break into half equations CN- -
ID: 602711 • Letter: C
Question
CN^-1 + MnO4 ^-1 = CNO-1 + MnO2 (basic)
Explanation / Answer
Break into half equations CN- -> CNO- equation 1 MnO4(1-) -> MnO2 equation 2 balance O using water, then use H+ to balance H, then cancel H+ using OH- (hence alkali conditions), then ad electrons to balance charges. CN- + H2O -> CNO- (add water) CN- + H2O -> CNO- + 2H+ (ad H+) CN- + H2O + 2OH- -> CNO- + 2H+ + 2OH- (cancel) CN- + 2OH- -> CNO- + H2O + 2e- (add electrons) MnO4(1-) -> MnO2 same as above MnO4(1-) + 2H2O + 3e- -> MnO2 + 4OH- Now make the electrons equal by multiplying the first equation by 3 and the second by 2 so now 3CN- + 6OH- -> 3 CNO- + 3H2O + 6e- 2MNO4(1-) + 4H2O + 6e- -> 2MnO2 + 8OH- and combine both equations while cancelling out species that occur on both sides leaving 3CN- + 2MnO4(1-) + H2O -> 3CNO- + 2MnO2 + 2OH-