Lesson Plan

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Lesson Plan
Grade: Date: 17/01/2026
Subject: Chemistry
Lesson Topic: Aldehydes and ketones: properties, reactions, tests
Learning Objective/s:
  • Describe structural differences between aldehydes and ketones and predict their physical properties.
  • Explain the mechanisms and outcomes of classical qualitative tests for carbonyl compounds.
  • Compare reactivity trends in nucleophilic addition and oxidation reactions of aldehydes versus ketones.
  • Apply knowledge to select appropriate reagents for reduction, Grignard addition, and acetal formation.
  • Analyse exam tips to identify α‑hydrogen presence and interpret test results.
Materials Needed:
  • Projector and screen for slide presentation
  • Whiteboard and markers
  • Handouts with summary tables of tests and reactions
  • Sample reagents (Fehling’s solution, Tollens’ reagent, 2,4‑DNP, NaBH4, Grignard reagent) or images for demonstration
  • Molecular model kits or 3‑D software
  • Exit‑ticket cards
 Introduction:
Begin with a quick demonstration of a silver mirror forming in Tollens’ test to capture interest. Review students’ prior knowledge of carbonyl functional groups and their general reactivity. State that by the end of the lesson they will be able to differentiate aldehydes and ketones using physical properties, qualitative tests, and reaction pathways.
Lesson Structure:
  1. Do‑now (5') – short quiz on carbonyl structures and boiling‑point trends.
  2. Mini‑lecture (10') – compare structural features, physical properties, and reactivity of aldehydes vs ketones using slides.
  3. Interactive demonstration (15') – perform (or view video of) Fehling’s and Tollens’ tests, discuss observations and write balanced equations.
  4. Guided practice (12') – small groups analyse unknown samples, choose appropriate tests, and predict results on a worksheet.
  5. Reaction pathways activity (10') – work through reduction, Grignard addition, and acetal formation mechanisms on the whiteboard.
  6. Quick check (5') – exit‑ticket question: “Which test distinguishes an aldehyde with an α‑hydrogen from a ketone and why?”
  7. Homework assignment (2') – assign textbook problems on nucleophilic addition and oxidation of carbonyl compounds.
Conclusion:
Summarise how structural differences dictate physical properties and test outcomes, reinforcing the key reactions covered. Ask students to complete the exit‑ticket and reflect on one test they found most diagnostic. Remind them to finish the assigned worksheet for homework and review the summary handout before the next class.