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) → CrO₄^2-(aq) (basic solution)

Verified step by step guidance

1. Identify the oxidation states of chromium in Cr(OH)3 and CrO4^{2-}.
2. Determine the change in oxidation state to identify if it's an oxidation or reduction. Chromium goes from +3 in Cr(OH)3 to +6 in CrO4^{2-}, indicating oxidation.
3. Balance the chromium atoms on both sides of the equation.
4. Balance the oxygen atoms by adding H2O molecules to the side deficient in oxygen.
5. Balance the hydrogen atoms by adding OH^- ions to the side deficient in hydrogen, and then balance the charge by adding electrons to the appropriate side.

Key Concepts

Half-Reactions

Half-reactions are the individual oxidation or reduction processes that occur in a redox reaction. They represent the transfer of electrons, with oxidation involving the loss of electrons and reduction involving the gain of electrons. Understanding half-reactions is crucial for balancing redox equations and determining the overall reaction.

Oxidation and Reduction

Oxidation is defined as the process where an atom, ion, or molecule loses electrons, resulting in an increase in oxidation state. Conversely, reduction is the gain of electrons, leading to a decrease in oxidation state. Identifying which species is oxidized and which is reduced is essential for balancing redox reactions.

Basic Solution Conditions

In basic solutions, the presence of hydroxide ions (OH-) influences the balancing of half-reactions. When balancing in basic conditions, it is often necessary to add OH- ions to neutralize any H+ ions produced during the reaction. This adjustment ensures that the final balanced equation accurately reflects the conditions of the solution.