Questions on balancing redox reactions in basic medium

Balancing redox reactions in basic solution
Problems 1 - 10

Problem #1: OCN¯ + OCl¯ ---> CO₃²¯ + N₂ + Cl¯

Solution:

On initial inspection, this problem seems like it might require three half-reactions.

However, it only needs two half-reactions.

Balancing redox reactions - examples

This is because the oxidation number on the C does not change. The C is +4 in OCN¯ and also +4 in the carbonate.

1) Here are the two half-reactions:

OCN¯ ---> CO₃²¯ + N₂
OCl¯ ---> Cl¯

2) Balance them as if in acid solution:

4H₂O + 2OCN¯ ---> 2CO₃²¯ + N₂ + 8H⁺ + 6e¯
2e¯ + 2H⁺ + OCl¯ ---> Cl¯ + H₂O

3) Equalize the electrons:

4H₂O + 2OCN¯ ---> 2CO₃²¯ + N₂ + 8H⁺ + 6e¯
6e¯ + 6H⁺ + 3OCl¯ ---> 3Cl¯ + 3H₂O

4) Add:

H₂O + 2OCN¯ + 3OCl¯ ---> 2CO₃²¯ + N₂ + 3Cl¯ + 2H⁺

5) Convert to basic:

2OH¯ + 2OCN¯ + 3OCl¯ ---> 2CO₃²¯ + N₂ + 3Cl¯ + H₂O

Problem #2: Dentrification in soils and oceans occurs when the nitrate ion is red

balancing redox reactions in basic solution practice problems

balancing redox reactions in basic solution worksheet with answers