Predict whether aqueous solutions of the following substances are acidic, basic, or neutral: (e) Na2SO3.

Verified step by step guidance

1. Identify the ions produced when \( \text{Na}_2\text{SO}_3 \) dissolves in water: \( \text{Na}^+ \) and \( \text{SO}_3^{2-} \).
2. Recognize that \( \text{Na}^+ \) is a spectator ion and does not affect the pH of the solution.
3. Consider the behavior of the \( \text{SO}_3^{2-} \) ion in water. It can react with water to form \( \text{HSO}_3^- \) and \( \text{OH}^- \), indicating a basic solution.
4. Write the hydrolysis reaction: \( \text{SO}_3^{2-} + \text{H}_2\text{O} \rightarrow \text{HSO}_3^- + \text{OH}^- \).
5. Conclude that the presence of \( \text{OH}^- \) ions makes the solution basic.

Key Concepts

Acid-Base Theory

Acid-base theory explains the behavior of substances in terms of their ability to donate protons (H+) or accept protons. According to the Brønsted-Lowry theory, acids are proton donors and bases are proton acceptors. Understanding this theory is essential for predicting the acidity or basicity of a solution based on the ions produced when a substance dissolves in water.

Salt Hydrolysis

Salt hydrolysis occurs when an ionic compound dissolves in water and its constituent ions interact with water molecules, potentially affecting the pH of the solution. In the case of Na2SO3, the sodium ions (Na+) are neutral, while the sulfite ions (SO3^2-) can react with water to produce hydroxide ions (OH-), leading to a basic solution. This concept is crucial for determining the resulting pH of the solution.

pH Scale

The pH scale measures the acidity or basicity of a solution, ranging from 0 (very acidic) to 14 (very basic), with 7 being neutral. A pH less than 7 indicates an acidic solution, while a pH greater than 7 indicates a basic solution. Understanding the pH scale is important for interpreting the results of acid-base reactions and predicting the nature of solutions formed from various substances.