Question

For a particular redox reaction SO_3^2-– is oxidized to SO_4^2- and Cu^+2 is reduced to Cu . Complete and balance the equation for this reaction in basic solution. Phases are optional.

Answer 1

Answer:

SO₃²⁻ + Cu²⁺ + 2OH⁻ ⟶ Cu + SO₄²⁻ + H₂O

Explanation:

I find that the easiest way to balance an equation in basic solution is first to balance as if it were in acid and then convert to base.

Your skeleton equation is

SO₃²⁻ + Cu²⁺ ⟶ SO₄²⁻ + Cu

1. Separate the reaction into two half-reactions

SO₃²⁻ ⟶ SO₄²⁻

Cu²⁺ ⟶ Cu

2. Balance all atoms other than O and H

Done

3. Balance O

SO₃²⁻ + H₂O ⟶ SO₄²⁻

Cu²⁺ ⟶ Cu

4. Balance H

SO₃²⁻ + H₂O ⟶ SO₄²⁻ + 2H⁺

Cu²⁺ ⟶ Cu

5. Balance charge

SO₃²⁻ + H₂O ⟶ SO₄²⁻ + 2H⁺ + 2e⁻

Cu²⁺ + 2e⁻ ⟶ Cu

6. Equalize electrons transferred

1 × [ SO₃²⁻ + H₂O ⟶ SO₄²⁻ + 2H⁺ + 2e⁻]

1 × [ Cu²⁺ + 2e⁻ ⟶ Cu]

7. Add the two half-reactions

SO₃²⁻ + H₂O ⟶ SO₄²⁻ + 2H⁺ + 2e⁻]

Cu²⁺ + 2e⁻ ⟶ Cu                                      

SO₃²⁻ + Cu²⁺ + H₂O ⟶ Cu + SO₄²⁻ + 2H⁺

8. Convert to base

SO₃²⁻ + Cu²⁺ + H₂O ⟶ Cu + SO₄²⁻ + 2H⁺

            2H⁺ + 2OH⁻ ⟶ 2H₂O                      

SO₃²⁻ + Cu²⁺ + 2OH⁻ ⟶ Cu + SO₄²⁻ + H₂O