Level 1 — Basic Recall (1–10)

1. Define a “phase.”

2. What is a phase boundary?

3. What is meant by vapour pressure?

4. Define boiling point.

5. What is Raoult’s Law?

6. What is an ideal solution?

7. What is a liquid–vapour equilibrium?

8. What is the triple point?

9. Define the critical temperature.

10. What is an azeotrope?

Level 2 — Understanding (11–20)

11. Explain why vapour pressure increases with temperature.

12. Why is boiling point reached when vapour pressure equals external pressure?

13. Explain why the vapour pressure of a solution is lower than that of a pure solvent.

14. Distinguish between ideal and non-ideal solutions.

15. Describe how intermolecular forces influence deviation from Raoult’s law.

16. Explain the difference between positive and negative deviations.

17. Why do azeotropes form?

18. Describe what happens at the critical point.

19. Explain why solids generally have lower vapour pressures than liquids.

20. Describe the shape of a phase diagram for water.

Level 3 — Application (21–30)

21. Predict how vapour pressure changes when a non-volatile solute is added.

22. Draw and label a typical phase diagram for CO₂.

23. Explain why water expands upon freezing using its phase diagram.

24. Use Raoult’s Law to calculate total vapour pressure of an ideal binary solution.

25. Identify an azeotrope from a vapour-pressure composition graph.

26. Predict whether ethanol–water forms a maximum or minimum boiling azeotrope.

27. Determine how pressure affects the boiling point of a liquid.

28. Predict the effect of decreasing external pressure on evaporation rate.

29. Use a phase diagram to determine the stable phase at a given P–T condition.

30. Predict the vapour pressure of a solution if given mole fractions and pure vapour pressures.

Level 4 — Analysis (31–40)

31. Analyse why some mixtures show positive deviation from Raoult’s Law.

32. Compare intermolecular interactions in ideal vs non-ideal solutions.

33. Explain the thermodynamic reason for lowering vapour pressure upon adding solute.

34. Discuss how Raoult’s Law applies to partial pressures in binary mixtures.

35. Explain the existence of minimum-boiling azeotropes using molecular attractions.

36. Use a phase diagram to explain sublimation at high altitudes.

37. Compare vapour pressure curves of volatile vs non-volatile liquids.

38. Analyse why fractional distillation fails for azeotropic mixtures.

39. Predict temperature at which a substance will sublimate using its phase diagram.

40. Explain why negative deviations lead to maximum vapour pressure reduction.

Level 5 — Exam/Challenge (41–50)

41. For a binary solution obeying Raoult’s Law, derive the equation for total vapour pressure.

42. Discuss, with examples, how deviations from Raoult’s Law arise due to:

43. Hydrogen bonding

44. Dipole interactions

45. Dispersion forces

46. Calculate composition of vapour phase given liquid composition and vapour pressures.

47. Explain why azeotropes cannot be separated by ordinary fractional distillation.

48. Analyse a given phase diagram to identify triple point, critical point, and equilibrium lines.

49. Evaluate the conditions under which supercritical fluids form and their uses.

50. Use a P–T phase diagram to justify why CO₂ does not exist as a liquid at atmospheric pressure.

51. Discuss why Raoult’s Law fails at high solute concentration (activity coefficients).

52. Given multiple data points, determine whether a mixture shows positive or negative deviation.

53. Derive the qualitative relationship between vapour pressure lowering and entropy of mixing.