pH and Solubility

Ethan Taylor
7 min read
Listen to this study note
Study Guide Overview
This study guide covers how pH affects solubility using Le Chatelier's Principle. It explains the impact of acidic and basic solutions on compounds with basic or acidic conjugate bases, the common ion effect, and why pH-neutral compounds are generally unaffected. It includes examples, practice questions, and emphasizes qualitative understanding over calculations for the AP exam.
#pH and Solubility: A Last-Minute Review 🚀
Hey, you've got this! Let's quickly review how pH affects solubility, focusing on the key ideas you'll need for the AP exam. Remember, it's all about how equilibrium shifts with changing conditions.
#The Big Picture: pH, Solubility, and Equilibrium
- pH tells us the concentration of H⁺ (and OH⁻) ions in a solution.
- Solubility is all about how much of a substance dissolves in a solution, and it's an equilibrium process. ⚖️
- Le Chatelier's Principle is our guide: If we change a condition (like pH), the equilibrium will shift to counteract that change.
- The common ion effect can also influence solubility by adding an ion that's already part of the equilibrium.
#### Effects of Acidic Solutions 🍋
- Key Idea: Acidic solutions (high [H⁺]) generally increase the solubility of compounds with basic conjugate bases.
- Why? The H⁺ ions react with the basic conjugate base (A⁻) to form HA, reducing [A⁻], and shifting the equilibrium towards dissolution.
- The weaker the acid, the more basic its conjugate base, and the more its solubility is affected by pH.
- Example: Fe(OH)₃ solubility increases in acidic solutions because H⁺ ions react with OH⁻, reducing [OH⁻] and pushing the dissolution equilibrium to the right.
Remember: More basic anions = more soluble in acidic solutions. Think of it like opposites attracting! 🧲

How are we doing?
Give us your feedback and let us know how we can improve