Question

Click in the answer box to activate the palette. Use the half-reaction method to balance the following equation in acidic solution. It is not necessary to include any phases of matter for any species. CN− + MnO4− → CNO− + MnO2

Answer 1

Answer:

The balanced reaction in the acidic medium is:

$2MnO4^-+3CN^-+2H^+\rightarrow 2MnO_2+H_2O+3CNO^-$

Explanation:

$CN^- + MnO4^-\rightarrow CNO^- + MnO_2$

1) $CN^-\rightarrow CNO^-$ ( oxidation)

Balance oxygen by adding water :

$CN^-+H_2O\rightarrow CNO^-$

Now , balance hydrogen by adding hydrogen ions on the side where hydrogen are less.

$CN^-+H_2O\rightarrow CNO^-+2H^+$

Add electrons to balance charge where positive charge is more.

$CN^-+H_2O\rightarrow CNO^-+2H^++2e^-$..[1]

2) $MnO4^-\rightarrow MnO_2$ (reduction)

Balance oxygen by adding water :

$MnO4^-\rightarrow MnO_2+2H_2O$

Now , balance hydrogen by adding hydrogen ions by adding them on the side where hydrogen are less.

$MnO4^-+4H^+\rightarrow MnO_2+2H_2O$..[2]

Add electrons to balance charge where positive charge is more.

$MnO4^-+4H^++3e^-\rightarrow MnO_2+2H_2O$..[2]

3 × [1] + 2 × [2]

The balanced reaction in the acidic medium is:

$2MnO4^-+3CN^-+2H^+\rightarrow 2MnO_2+H_2O+3CNO^-$