Level 1 — Basic Recall (1–10)

1. What is Nernst Distribution Law?

2. Define the partition (distribution) coefficient, K.

3. In what type of system does distribution law apply?

4. What two phases are involved in distribution?

5. Give an example of a solute that can distribute between two solvents.

6. State one requirement for Nernst distribution law to hold.

7. What does the symbol ( C_1 ) represent in the law?

8. What does the symbol ( C_2 ) represent in the law?

9. What is meant by a “mutually immiscible solvent pair”?

10. Define solvent extraction.

Level 2 — Understanding (11–20)

11. Explain why solute distributes between two solvents.

12. Why must the solute exist in the same molecular form in both solvents?

13. How does polarity affect the partitioning of a solute?

14. Why does distribution reach equilibrium?

15. Describe the effect of temperature on partition coefficient.

16. What happens when the solute associates (dimerizes) in one phase?

17. What happens when the solute dissociates in one phase?

18. Explain why “multiple extractions” are more efficient than one large extraction.

19. What does a high partition coefficient indicate about solute preference?

20. Why is shaking important during solvent extraction?

Level 3 — Application (21–30)

21. Write the expression for partition coefficient for solute X in solvents A and B.

22. Calculate partition coefficient given concentrations in two layers.

23. Predict distribution of iodine between CCl₄ and water.

24. Use distribution law to calculate the amount of solute extracted into organic layer.

25. Given masses before and after extraction, calculate extraction efficiency.

26. Apply the rule “like dissolves like” to distribution behaviour.

27. Predict which solvent (polar vs non-polar) caffeine prefers.

28. Explain why dye extraction from water into benzene follows distribution law.

29. Given K and initial amount, calculate remaining solute after one extraction.

30. Calculate concentration ratio after two successive extractions.

Level 4 — Analysis (31–40)

31. Analyse changes in distribution when solute ionizes in aqueous phase.

32. Show how the distribution law modifies when the solute associates (e.g., dimerizes).

33. Explain why extraction efficiency improves with increased surface area of contact.

34. Compare extraction efficiency of many small extractions vs one large extraction.

35. Analyse how pH affects distribution of weak acids and weak bases.

36. Explain why amines extract better into organic phase in basic conditions.

37. Examine deviations from distribution law in non-ideal solutions.

38. Compare distribution behaviour in two solvents with different dielectric constants.

39. Predict how temperature shifts equilibrium distribution for an exothermic dissolution.

40. Explain how complex formation (e.g., metal-ligand) affects partitioning.

Level 5 — Exam/Challenge (41–50)

41. Derive the formula for fraction of solute extracted using a single extraction.

42. Derive the formula for fraction remaining after n successive extractions.

43. Given experimental data, determine whether solute associates in one phase.

44. Evaluate the effect of ionic strength on distribution of a neutral solute.

45. Calculate the number of extractions required to remove 99% of solute.

46. Analyse distribution behaviour when solute exists as HA in organic phase and A⁻ in aqueous phase (acid–base extraction).

47. Given K and solvent volumes, compute final equilibrium concentrations for multi-step extraction.

48. Explain how distribution law applies to chromatography (partition chromatography).

49. Evaluate limitations of the distribution law in real laboratory conditions.

50. Propose an optimized extraction procedure for maximizing separation of two solutes with different partition coefficients.