Determine whether each cation is acidic or pH-neutral. For those cations that are acidic, write an equation that shows how the cation acts as an acid. c. Co³⁺

Key Concepts

Acidic Cations

Acidic cations are positively charged ions that can donate protons (H+) in solution, thereby lowering the pH. These cations typically arise from transition metals and can interact with water to form hydronium ions (H3O+). Understanding whether a cation is acidic involves examining its charge and the nature of its interactions with water.

Hydrolysis of Metal Ions

Hydrolysis refers to the reaction of a metal ion with water, leading to the formation of an acidic solution. When a metal cation like Co3+ is dissolved in water, it can attract water molecules, resulting in the release of protons and the formation of a complex ion. This process is crucial for determining the acidity of the cation in solution.

pH and Acidity

pH is a measure of the hydrogen ion concentration in a solution, indicating its acidity or basicity. A pH less than 7 signifies an acidic solution, while a pH of 7 is neutral. Understanding the relationship between cations and pH is essential for determining whether a cation is acidic or neutral, as acidic cations will typically lower the pH of the solution.