Textbook Question
Balance the half-reactions in Problem 19.43, assuming that they occur in basic solution.
Ch.19 - Electrochemistry
Chapter 19, Problem 47a
Write unbalanced oxidation and reduction half-reactions for the following processes. (a) Mn(s) + NO3-(aq) → Mn2+(aq) + NO2(g)
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Identify the species being oxidized and reduced. Mn is oxidized to Mn^{2+}, and NO_3^- is reduced to NO_2.
Write the oxidation half-reaction. Mn(s) → Mn^{2+}(aq)
Write the reduction half-reaction. NO_3^-(aq) → NO_2(g)
Ensure that each half-reaction is unbalanced, focusing only on the change in oxidation states.
Remember that in the oxidation half-reaction, Mn goes from 0 to +2, and in the reduction half-reaction, N goes from +5 in NO_3^- to +4 in NO_2.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Oxidation and Reduction
Oxidation and reduction (redox) reactions involve the transfer of electrons between species. Oxidation refers to the loss of electrons, resulting in an increase in oxidation state, while reduction is the gain of electrons, leading to a decrease in oxidation state. In the given reaction, manganese (Mn) is oxidized to Mn²⁺, and the nitrate ion (NO₃⁻) is reduced to nitrogen dioxide (NO₂).
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Oxidation and Reduction Reactions
Half-Reactions
Half-reactions are used to represent the oxidation and reduction processes separately in a redox reaction. Each half-reaction shows either the loss of electrons (oxidation) or the gain of electrons (reduction), allowing for a clearer understanding of the electron transfer. In this case, one half-reaction will depict the oxidation of Mn to Mn²⁺, while the other will illustrate the reduction of NO₃⁻ to NO₂.
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Balancing Redox Reactions
Balancing redox reactions involves ensuring that the number of atoms and the charge are equal on both sides of the equation. This is typically done by adjusting coefficients and adding electrons to the half-reactions. In the provided process, it is essential to balance the charges and atoms after writing the unbalanced half-reactions to ensure the overall reaction adheres to the law of conservation of mass and charge.
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Related Practice
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