Chapter 15 2-1 Common Ion Effect

The common ion effect uses Le Chatalier's Principle.
BaSO4(2) == Ba2+ (aq) + SO42- (aq)
1. Adding a source of Ba2+ would cause a shift to the left
2. Adding a source of SO42- would cause a shift to the right
3. adding H+ would react with the SO42- to decrease SO42- concentration and cause a shift to the right.

Problem: What is [Ag+] in 0.1 M chloride solution?
Step 1: Write Ksp for silver chloride (AgCl)
Step 2: Write Ksp expression Ksp = [Ag+][Cl-]
Step 3: Substitute in Ksp and [Cl-] = 0.1 into equation and solve for [Ag+]
~ This assumes that the Ksp are quite small, which they usually are.