Balancing Redox Reactions Video Lessons

Concept

# Problem: When the reactionMnO4–(aq) + CN–(aq) → MnO2(s) + CNO–(aq)is balanced in a basic medium, what are the sum of the coefficients?A) 20B) 10C) 8D) 13E) 11

###### FREE Expert Solution

We are being asked to determine the are the sum of the coefficients when the reaction is balanced in a basic medium.

When balancing redox reactions under basic conditions, we will follow the following steps.

Step 1: Separate the whole reaction into half-reactions
Step 2: Balance the non-hydrogen and non-oxygen elements first
Step 3: Balance oxygen by adding H2O to the side that needs oxygen (1 O: 1 H2O)
Step 4: Balance hydrogen by adding H+ to the side that needs hydrogen (1 H: 1 H+)
Step 5: Balance the charges: add electrons to the more positive side (or less negative side)
Step 6: Balance electrons on the two half-reactions
Step 7: Get the overall reaction by adding the two reaction
Step 8: Balance remaining H+ by adding an equal amount of OH- ions to both sides
Step 9: H+(aq) will combine with OH-(aq) to form H2O(l)­
Step 10: Cancel out common species.

Balance the redox reaction under basic condition:

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###### Problem Details

When the reaction

MnO4(aq) + CN(aq) → MnO2(s) + CNO(aq)

is balanced in a basic medium, what are the sum of the coefficients?

A) 20

B) 10

C) 8

D) 13

E) 11