🎯 Objective
Study the effect on pH of acetic acid solution when sodium acetate (common ion: CH₃COO⁻) is added.
Theory
Equilibrium
CH₃COOH ⇌ H⁺ + CH₃COO⁻
Common Ion Effect
Adding CH₃COO⁻ shifts equilibrium LEFT (Le Chatelier's principle)
Result
[H⁺] decreases → pH increases
Henderson Equation
pH = pKa + log([A⁻]/[HA])
pH Meter
2.87
0 (Acidic)
7 (Neutral)
14 (Basic)
Equilibrium State
CH₃COOH
⇌
H⁺ +
CH₃COO⁻
At equilibrium
H⁺ H⁺ H⁺
0.1 M CH₃COOH
No salt added
Add Sodium Acetate (CH₃COONa)
📊 Observations
| [CH₃COONa] | pH |
|---|---|
| 0 M | 2.87 |
Lab Notebook
Observations will appear here...