1. Experiment Snapshot
| Feature | Details |
|---|
| Experiment | Potassium Permanganate Titration |
| Exam Importance | ⭐⭐⭐⭐ Practical exam standard |
| Typical Marks | 5–15 marks |
2. Aim
To carry out a potassium permanganate titration and identify the endpoint using its self-indicating colour change.
3. Quick Theory
Potassium permanganate is purple and acts as its own indicator. In acidic solution it is reduced from MnO4- to Mn2+.
Examiner Tip: Always connect the observation or reading to the purpose of the experiment.
4. Apparatus and Chemicals
| Apparatus | Chemicals |
|---|
| Burette, pipette, conical flask, white tile. | Potassium permanganate solution, reducing agent and dilute sulfuric acid. |
Safety: Wear goggles and follow teacher instructions, especially with acids, alkalis, hot apparatus and oxidising agents.
5. Step-by-Step Procedure
- Acidify the reducing agent with dilute sulfuric acid.
- Fill the burette with potassium permanganate.
- Titrate while swirling.
- Stop when a permanent pale pink colour remains.
- Repeat for concordant titres.
6. Observations / Results
| Situation | Expected Result |
|---|
| During titration | Purple colour disappears. |
| Endpoint | Permanent pale pink colour. |
7. Student Common Mistakes
- Using hydrochloric acid instead of sulfuric acid.
- Adding an external indicator.
- Overshooting the pale pink endpoint.
- Not acidifying the solution.
8. Examiner Traps
Trap: Students often describe the apparatus but forget the exact observation, reading, or endpoint. Use precise words.
8A. Labelled Diagram
Potassium permanganate is useful because it is self-indicating. The purple colour fades during the reaction, and the endpoint is a very light pink.
Potassium Permanganate Titration
The permanganate colour itself tells you when the titration is finished.
Teacher Voice: Make students say the endpoint out loud as “a permanent pale pink” because that wording earns marks.
9. 🎮 Interactive Simulator
Try It Yourself
Is an external indicator needed?
What is the endpoint?
Result Window
Ready
Choose the correct actions to complete the practical.
Score: 0/0
10. Past Paper Style Questions
- State the aim of this experiment. [2]
- Describe the procedure in order. [4]
- State one safety precaution. [2]
- State one common error and one improvement. [4]
- Explain the key observation/result. [3]
11. Mark Scheme
Aim correct [2].
Procedure in correct order [4].
Safety precaution [2].
Error and improvement [4].
Observation/result explained [3].
12. Mastery Checklist
- I can state the aim.
- I can name the apparatus and chemicals.
- I can describe the method in order.
- I know the result or endpoint.
- I can avoid student common mistakes.
- I can answer Section A questions.