Describe an activity to show that compounds like glucose and alcohol contain hydrogen but are not acids.
Generated by claude-sonnet-4-6 · 2026-06-17 12:37 · grounding rag
Model Answer
Activity 2.8 — Electrical Conductivity Test
Materials required: Solutions of glucose, alcohol, dilute HCl, dilute H₂SO₄; two nails fixed on a cork, a 100 mL beaker, a 6V battery, a bulb, and connecting wires.
Procedure:
- Fix two nails on a cork and place it in a beaker. Connect the nails to a 6V battery through a bulb and switch.
- Pour dilute HCl into the beaker and switch on the current. Observe whether the bulb glows.
- Repeat with dilute H₂SO₄.
- Repeat separately with glucose solution and alcohol solution.
Observation:
- The bulb glows with dilute HCl and H₂SO₄.
- The bulb does not glow with glucose and alcohol solutions.
Conclusion:
Acids (HCl, H₂SO₄) produce H⁺(aq) ions in solution, which carry electric current. Glucose and alcohol do not ionise in water — they produce no H⁺ ions — so they do not conduct electricity and are not acids, even though they contain hydrogen.
Source: Chapter 2, Activity 2.8, Section 2.2
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Explanation
- Why the bulb test works: Current flows only when ions are present. Acids ionise → H⁺ + anion → bulb glows. Glucose/alcohol stay as molecules → no ions → bulb stays off.
- Key conclusion examiners want: Simply containing hydrogen is not enough to be an acid; the compound must produce H⁺(aq) ions in solution.
- Marks breakdown (5 marks): ~1 mark for materials/setup, ~1 mark for procedure steps, ~1 mark for observation (both cases), ~2 marks for conclusion with ionic explanation. Always state the inference explicitly.