Write balanced net ionic equations for the following reactions in acidic solution. (b) TeO₂(s) + Cr²⁺(aq) → Te(s) + Cr³⁺(aq)

Verified step by step guidance

1. Step 1: Identify the oxidation and reduction processes. TeO₂ is reduced to Te, and Cr²⁺ is oxidized to Cr³⁺.
2. Step 2: Write the half-reactions for the oxidation and reduction processes. Reduction: TeO₂(s) → Te(s). Oxidation: Cr²⁺(aq) → Cr³⁺(aq).
3. Step 3: Balance the atoms other than O and H in each half-reaction. The reduction half-reaction is already balanced for Te, and the oxidation half-reaction is balanced for Cr.
4. Step 4: Balance the oxygen atoms by adding H₂O to the side that needs oxygen. For the reduction half-reaction: TeO₂(s) + 2H₂O(l) → Te(s).
5. Step 5: Balance the hydrogen atoms by adding H⁺ to the side that needs hydrogen. Then, balance the charges by adding electrons. Combine the balanced half-reactions to form the net ionic equation.

Key Concepts

Net Ionic Equations

Net ionic equations represent the actual chemical species that participate in a reaction, excluding spectator ions. They focus on the ions and molecules that undergo a change during the reaction, providing a clearer picture of the chemical processes involved. To write a net ionic equation, one must first write the complete ionic equation and then eliminate the spectator ions.

Acidic Solution

An acidic solution is characterized by a higher concentration of hydrogen ions (H⁺) than hydroxide ions (OH⁻). In such environments, certain reactions may proceed differently due to the presence of H⁺ ions, which can influence the oxidation states of elements and the overall reaction pathway. Understanding the role of acidity is crucial for predicting the products and balancing the equations correctly.

Oxidation and Reduction

Oxidation and reduction (redox) reactions involve the transfer of electrons between species, leading to changes in their oxidation states. In the given reaction, TeO₂ is reduced to Te, while Cr²⁺ is oxidized to Cr³⁺. Identifying which species is oxidized and which is reduced is essential for balancing the net ionic equation and understanding the underlying chemical transformations.