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Ch.20 - Electrochemistry
Brown - Chemistry: The Central Science 14th Edition
Brown14th EditionChemistry: The Central ScienceISBN: 9780134414232Not the one you use?Change textbook
All textbooksBrown 14th EditionCh.20 - ElectrochemistryProblem 25e
Chapter 20, Problem 25e

Complete and balance the following equations, and identify the oxidizing and reducing agents: MnO4-(aq) + Br-(aq) → MnO2(s) + BrO3-(aq) (basic solution)

Verified step by step guidance
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Step 1: Separate the reaction into two half-reactions, one for oxidation and one for reduction. Identify the species being oxidized and reduced.
Step 2: Balance each half-reaction for mass and charge. Start by balancing all elements except for oxygen and hydrogen. Then, balance oxygen atoms by adding H2O molecules, and balance hydrogen atoms by adding OH- ions (since the solution is basic). Finally, balance the charges by adding electrons.
Step 3: Multiply each half-reaction by an appropriate coefficient so that the number of electrons lost in the oxidation half-reaction equals the number of electrons gained in the reduction half-reaction.
Step 4: Add the balanced half-reactions together, canceling out any species that appear on both sides of the equation, such as electrons, water, or hydroxide ions.
Step 5: Identify the oxidizing agent (the species that is reduced) and the reducing agent (the species that is oxidized) in the balanced equation.

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Oxidation-Reduction Reactions

Oxidation-reduction (redox) reactions involve the transfer of electrons between species, resulting in changes in oxidation states. In these reactions, oxidation refers to the loss of electrons, while reduction refers to the gain of electrons. Understanding these processes is crucial for identifying the oxidizing and reducing agents in a chemical equation.
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Oxidation and Reduction Reactions

Balancing Redox Reactions

Balancing redox reactions requires ensuring that both mass and charge are conserved. This often involves separating the reaction into half-reactions for oxidation and reduction, balancing each half for atoms and charge, and then combining them. In basic solutions, hydroxide ions (OH-) may be added to balance the reaction, which is essential for achieving the correct stoichiometry.

Identifying Oxidizing and Reducing Agents

The oxidizing agent is the species that is reduced (gains electrons) during the reaction, while the reducing agent is the species that is oxidized (loses electrons). Identifying these agents is key to understanding the dynamics of the reaction and predicting the products formed. In the given equation, recognizing the changes in oxidation states helps in pinpointing these agents.
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Related Practice
Textbook Question

Complete and balance the following equations, and identify the oxidizing and reducing agents. (Recall that the O atoms in hydrogen peroxide, H2O2, have an atypical oxidation state.) H2O21aq2 + ClO21aq2 ¡ ClO2-1aq2 + O21g2 (basic solution)

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Textbook Question

Complete and balance the following equations, and identify the oxidizing and reducing agents: As2O3(s) + NO3-(aq) → H3AsO4(aq) + N2O3(aq) (acidic solution)

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Textbook Question

Complete and balance the following half-reactions. In each case indicate whether the half-reaction is an oxidation or a reduction. (g) Cr(OH)3(s) → CrO42-(aq) (basic solution)

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Textbook Question

A voltaic cell similar to that shown in Figure 20.5 is constructed. One electrode half-cell consists of a silver strip placed in a solution of AgNO3, and the other has an iron strip placed in a solution of FeCl2. The overall cell reaction is Fe1s2 + 2 Ag+1aq2 ¡ Fe2+1aq2 + 2 Ag1s2 (f) In which directions do the cations and anions migrate through the solution?

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Textbook Question

Complete and balance the following equations, and identify the oxidizing and reducing agents: (a) Cr2O72-(aq) + I-(aq) → Cr3+(aq) + IO3-(aq) (acidic solution) (b) MnO4-(aq) + CH3O(1aq) → Mn2+(aq) + HCOOH(aq) (acidic solution) (c) I2(s) + OCl-(aq) → IO3-(aq) + Cl-(aq) (acidic solution)

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