Balancing Redox Reactions Video Lessons

Concept

Problem: Balance the following redox reactions occurring in acidic aqueous solution.Cl−(aq)+NO3−(aq)→NO(g)+Cl2(g)Express your answer as a chemical equation. Identify all of the phases in your answer.

FREE Expert Solution

Balance the redox reaction under acidic conditions:

Cl(aq)+NO3(aq)→NO(g)+Cl2(g)

*Before balancing the redox reaction:

ignore H+, OH-, and H2O in the starting reaction

Step 1: Separate the whole reaction into two half-reactions

Cl(aq)Cl2(g)                                                         NO3(aq)NO(g)

Step 2: Balance the non-hydrogen and non-oxygen elements first

2Cl(aq)Cl2(g)                                                         NO3(aq)NO(g)

(Clbalanced)                                               (Nbalanced)

Step 3: Balance oxygen by adding H2O(l) to the side that needs oxygen (1 O : 1 H2O)

2Cl(aq)Cl2(g)                                                    NO3(aq)NO(g2H2O (l)

(No oxygens)

Step 4: Balance hydrogen by adding H+ to the side that needs hydrogen (1 H: 1 H+)

2Cl(aq)Cl2(g)                                                 4H+ (aq) + NO3(aq)NO(g2H2O (l)

(No hydrogens)

Step 5: Balance the charges: add electrons to the more positive side (or less negative side)

▪ For species that are neutral: oxidation state = 0

▪ For ions (or species with charges): oxidation state = charge of the ion

▪ The reactant side and the product side should have an equal overall charge (after adding electrons)

2Cl(aq)Cl2(g)                                                                  4H+ (aq) + NO3(aq)NO(g2H2O (l)

Reactants                            Products                               Reactants                            Products

2Cl- = 2(-1) =-2                       Cl2 = 0                                   NO3- = -1                                NO = 0

+2 e- = (-1) x 2 = -2             4H+ = 4(+1) = +4                     H2O = 0

-----------------------                 ------------------------                     +3 e- = (-1) x 3 = -3

overall = -2                             overall = -2                             -------------------------------              ----------------

overall = 0                          overall = 0

Problem Details

Balance the following redox reactions occurring in acidic aqueous solution.

Cl−(aq)+NO3−(aq)→NO(g)+Cl2(g)