Complete and balance the following equations, and identify the oxidizing and reducing agents: (a) Cr2O72-1aq2 + I-1aq2 ¡ Cr3+1aq2 + IO3-1aq2 (acidic solution)

Verified step by step guidance

1. Identify the oxidation states of each element in the reactants and products to determine which elements are oxidized and reduced.
2. Write separate half-reactions for the oxidation and reduction processes. For this reaction, identify the half-reaction where iodine (I) is oxidized to iodate (IO_3^-) and the half-reaction where dichromate (Cr_2O_7^{2-}) is reduced to chromium (Cr^{3+}).
3. Balance each half-reaction for mass and charge. Start by balancing the atoms other than O and H, then balance O atoms by adding H_2O, and H atoms by adding H^+. Finally, balance the charges by adding electrons (e^-).
4. Multiply each half-reaction by an appropriate factor so that the number of electrons lost in the oxidation half-reaction equals the number of electrons gained in the reduction half-reaction.
5. Add the balanced half-reactions together, canceling out the electrons and any other species that appear on both sides, to obtain the balanced overall equation. Identify the oxidizing agent (the species that is reduced) and the reducing agent (the species that is oxidized).

Key Concepts

Redox Reactions

Redox reactions, or oxidation-reduction reactions, involve the transfer of electrons between species. In these reactions, one substance is oxidized (loses electrons) while another is reduced (gains electrons). Understanding the changes in oxidation states of the elements involved is crucial for identifying the oxidizing and reducing agents.

Oxidizing and Reducing Agents

An oxidizing agent is a substance that gains electrons and is reduced in a chemical reaction, while a reducing agent is one that loses electrons and is oxidized. Identifying these agents is essential for understanding the dynamics of redox reactions, as they dictate the flow of electrons and the overall reaction mechanism.

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 often requires the use of half-reaction methods, where the oxidation and reduction processes are balanced separately before combining them. In acidic solutions, the addition of H+ ions and water may be necessary to achieve balance.