| Lesson Plan |
| Grade: |
Date: 25/02/2026 |
| Subject: Chemistry |
| Lesson Topic: State that aqueous solutions of acids contain $ \mathrm{H}^{+} $ ions and aqueous solutions of alkalis contain $ \mathrm{OH}^{-} $ ions |
Learning Objective/s:
- Describe the ionisation of acids and bases in aqueous solution.
- Identify the ions produced by acids ($\mathrm{H}^{+}$) and alkalis ($\mathrm{OH}^{-}$).
- Compare characteristic properties of acids and bases using litmus, taste and other indicators.
- Explain the neutralisation reaction between $\mathrm{H}^{+}$ and $\mathrm{OH}^{-}$ ions.
- Apply knowledge to predict the outcome of simple acid‑base reactions.
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Materials Needed:
- Projector or interactive whiteboard
- Chemistry textbook or handout on acids and bases
- Red and blue litmus paper
- Dilute acid (e.g., vinegar) and base (e.g., sodium hydroxide solution) samples
- Worksheets with comparison tables
- Safety goggles and gloves
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Introduction:
Begin with a quick demonstration: dip red and blue litmus paper into two clear solutions and observe the colour change. Recall that students already know acids taste sour and bases feel slippery. Explain that today they will link these observations to the ions present in solution and set the success criteria: they will be able to state which ion each solution contains and predict the result of a neutralisation.
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Lesson Structure:
- Do‑now (5') – Short quiz on properties of acids and bases displayed on the board.
- Mini‑lecture (10') – Explain ionisation of acids (HA → $\mathrm{H}^{+}$ + A⁻) and bases (MOH → M⁺ + $\mathrm{OH}^{-}$) with projected diagram.
- Guided inquiry (12') – In pairs, test litmus paper in the provided solutions and record which ion they infer.
- Comparison activity (8') – Complete a table contrasting acid vs. base properties, referencing the ion produced.
- Concept check (5') – Rapid‑fire questions; students hold up cards showing $\mathrm{H}^{+}$ or $\mathrm{OH}^{-}$.
- Consolidation (5') – Summarise neutralisation reaction and have students write the balanced equation.
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Conclusion:
Recap that acids release $\mathrm{H}^{+}$ ions and bases release $\mathrm{OH}^{-}$ ions, and that their combination forms water in a neutralisation reaction. Students complete an exit ticket by writing one real‑life example of an acid‑base reaction. For homework, assign a worksheet to classify common household substances as acids or bases.
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