1. 8.3 – Strong vs. Weak Acid & Base Titrations
Topic 8 – Acids & Bases
8.3 – Strong vs. Weak Acid & Base Titrations

2. Strong and Weak Acids and Bases
Objectives:
Understand the difference between strong and weak acids and bases
Complete an experiment to explore the difference in properties of strong/weak acids and bases

3. Strong and Weak Acids Strong Acids:
HA(aq)  H+(aq) + A ̶ (aq) …..the acid fully dissociates into ions
For example: HCl(aq)  H+(aq) + Cl ̶ (aq)
Includes: hydrochloric, sulfuric, phosphoric, nitric
Strong acids have weak conjugate bases
Weak Acids:
HA(aq)  H+(aq) + A ̶ (aq) …..the acid only partially dissociates into ions
For example: HF(aq)  H+(aq) + F ̶ (aq)
Includes: hydrofluoric, ethanoic, carbonic
Weak acids have strong conjugate bases

4. Strong and Weak Bases Strong Bases:
BOH(aq)  B+(aq) + OH ̶ (aq) …..the base fully dissociates into ions
For example: NaOH(aq)  Na+(aq) + OH ̶ (aq)
Includes: group (I) hydroxides, barium hydroxide
Strong bases have weak conjugate acids
Weak Bases:
BOH(aq)  B+(aq) + OH ̶ (aq) …..the base only partially dissociates into ions
For example: NH3(aq) + H2O(l)  NH4+(aq) + OH ̶ (aq)
Includes: ammonia, amines
Weak bases have strong conjugate acids

5. So what?
The equilibrium has a profound effect on the properties of the acid/base
Compared with strong acids of the same concentration, weak acids:
Have lower electrical conductivity
React more slowly
pH is higher (less acid)
Change pH more slowly when diluted
However, they neutralise the same volume of alkali
Weak bases follow a similar pattern

6. Strong Acid & Strong Base

7. Strong Acid & Weak Base

8. Weak Acid & Strong Base

9. Weak Acid & Weak Base

10. Compare Titration Curves

11. Simulation
solutions

12. Key Points Strong acids/bases dissociate fully into ions
Weak acids/bases only partially dissociate, forming an equilibrium
The strong/weak character has a significant effect on the chemical properties

13. Homework