20.1 Student Notes

I. Balancing Oxidation-Reduction Reactions

A. Half – reaction method

1. Oxidation –

2. Reduction –

3. Oxidizing agent –

4. Reducing agent –

5. Questions to help balance

a. What is being oxidized? What is being reduced?

b. What results from the oxidation and the reduction?

c. Does the reaction occur in acidic or basic solution?

B. Steps in balancing redox reaction in acidic solution

1.

2.

3. Complete and balance each half-reaction

a.

b.

c.

d.

4. Combine the two half-reactions

a.

b.

C. Balancing Equations by the Half-Reaction Method (Acidic Solution)

Zinc metal reacts with nitric acid, HNO₃, to produce a number of products depending on how dilute the acid solution is. In a concentrated solution, zinc reduces nitrate ion to ammonium ion; zinc is oxidized to zinc ion, Zn²⁺. Write the net ionic equation for this reaction.

D. Additional Steps for Balancing Oxidation-Reduction Equations in Basic Solution

5.

6.

E. Balancing Equations by the Half-Reaction Method (Basic Solution)

Permanganate ion oxidizes sulfite ion in basic solution according to the following skeleton equation:

MnO₄^- (aq) + SO₃^2- (aq) à MnO₂ (s) + SO₄^2- (aq)

Use the half-reaction method to complete and balance this equation.