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Balancing Oxidation-Reduction Reactions

Grade 12 Chemistry worksheet on balancing redox reactions using the half-reaction method in acidic and basic solutions.

Grade 12 Science ChemistryRedox Reactions and ElectrochemistryBalancing Oxidation Reduction Reactions
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Multiple ChoiceFill in the Blanks2 Short AnswerTrue / FalseLong Answer

Standards

HS-PS1-2HS-PS1-7
8 sections · Free to use · Printable
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Balancing Oxidation-Reduction Reactions

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Read each question carefully and follow the instructions to balance the given oxidation-reduction reactions. Show all your work for full credit.

1. In the reaction: MnO₄⁻(aq) + C₂O₄²⁻(aq) → Mn²⁺(aq) + CO₂(g) (acidic solution), what is the oxidation state of carbon in C₂O₄²⁻?

a

+2

b

+3

c

+4

d

+6

2. Which of the following acts as the oxidizing agent in the reaction: Cr₂O₇²⁻(aq) + SO₃²⁻(aq) → Cr³⁺(aq) + SO₄²⁻(aq) (acidic solution)?

a

Cr₂O₇²⁻

b

SO₃²⁻

c

Cr³⁺

d

SO₄²⁻

3. In an acidic solution, to balance oxygen atoms, we add   to the side lacking oxygen.

4. To balance hydrogen atoms in a basic solution, we first add H⁺ ions, then add an equal number of   to both sides of the equation.

5. Balance the following redox reaction in acidic solution:

IO₃⁻(aq) + I⁻(aq) → I₂(s)

6. Balance the following redox reaction in basic solution:

MnO₄⁻(aq) + Br⁻(aq) → MnO₂(s) + BrO₃⁻(aq)

7. The number of electrons gained in a reduction half-reaction must equal the number of electrons lost in an oxidation half-reaction.

T

True

F

False

8. When balancing a redox reaction, spectator ions are typically included in the half-reactions.

T

True

F

False

9. Explain the key differences in balancing redox reactions in acidic versus basic solutions, specifically regarding the use of H⁺, OH⁻, and H₂O.