Predict whether aqueous solutions of the following compounds are acidic, basic, or neutral: (c) Na2CO3

Verified step by step guidance

1. Identify the ions formed when Na2CO3 dissolves in water: Na2CO3 dissociates into 2 Na^+ ions and 1 CO3^2- ion.
2. Recognize that Na^+ is a spectator ion, which does not affect the acidity or basicity of the solution.
3. Focus on the CO3^2- ion, which is the conjugate base of the weak acid H2CO3 (carbonic acid).
4. Understand that CO3^2- can react with water in a hydrolysis reaction to form HCO3^- and OH^-: CO3^2- + H2O ⇌ HCO3^- + OH^-.
5. Conclude that the presence of 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, while bases are proton acceptors. Understanding this theory is essential for predicting the acidity or basicity of a solution.

Salt Hydrolysis

Salt hydrolysis occurs when an ionic compound dissolves in water and its ions interact with water molecules, potentially affecting the pH of the solution. In the case of Na2CO3, the carbonate ion (CO3^2-) can react with water to produce hydroxide ions (OH-), leading to a basic solution. This concept is crucial for determining the nature 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 helps in predicting the behavior of solutions, such as those formed by Na2CO3.