13.4 Equilibria for Weak Acids and Bases
pH Calculations for Weak Acids & Bases
| Acid | Ka |
|---|---|
| HF | 6.8 × 10-4 |
| HC2H3O2 | 1.76 × 10-5 |
| HCN | 4.9 × 10-10 |
KaKb = Kw
A stronger acid has a larger Ka / smaller pKa.
A stronger base has a larger Kb / smaller pKb.
The stronger the acid, the weaker the conjugate base and vice versa.
What is the pH of a 0.1M solution of acetic acid (Ka = 1.76 × 10-5)?
What is the Ka of a weak acid, HA, if the pH of a 0.1M solution is 3?
What is the pH of a 0.1M solution of ammonia (Kb = 1.75 × 10-5)?