Textbook Question
Complete and balance the following half-reactions in basic solution. In each case, indicate whether the half-reaction is an oxidation or a reduction. c. Cr(OH)3(𝑠)⟶CrO42−(𝑎𝑞)
6. Chemical Quantities & Aqueous Reactions
Balancing Redox Reactions: Basic Solutions
Multiple Choice
Which of the following is the correctly balanced redox reaction for H2O2(aq) + ClO2(aq) → ClO₂⁻(aq) + O₂(g) in a basic solution?
A
H2O2(aq) + ClO2(aq) + OH⁻(aq) → ClO₂⁻(aq) + O₂(g) + H2O(l)
B
H2O2(aq) + ClO2(aq) → ClO₂⁻(aq) + O₂(g) + OH⁻(aq)
C
H2O2(aq) + ClO2(aq) + 2OH⁻(aq) → ClO₂⁻(aq) + O₂(g) + 2H2O(l)
D
H2O2(aq) + ClO2(aq) + H2O(l) → ClO₂⁻(aq) + O₂(g) + OH⁻(aq)
Verified step by step guidance1
Identify the oxidation and reduction half-reactions. In this case, H₂O₂ is being oxidized to O₂, and ClO₂ is being reduced to ClO₂⁻.
Write the oxidation half-reaction: H₂O₂ → O₂. Balance the oxygen atoms by adding H₂O to the right side: H₂O₂ → O₂ + H₂O.
Balance the hydrogen atoms by adding H⁺ to the left side: H₂O₂ + 2H⁺ → O₂ + H₂O.
Write the reduction half-reaction: ClO₂ → ClO₂⁻. Balance the oxygen atoms by adding H₂O to the left side: ClO₂ + H₂O → ClO₂⁻.
Combine the balanced half-reactions, ensuring that the electrons cancel out, and adjust for basic conditions by adding OH⁻ to both sides to neutralize H⁺ and form water. The final balanced equation in basic solution is: H₂O₂ + ClO₂ + 2OH⁻ → ClO₂⁻ + O₂ + 2H₂O.
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