The d-and f-Block Elements Mock Test – Class 12 Chemistry

1. Use the following stability description. State P is favoured in a strongly oxidising oxide lattice. State Q is favoured as a hydrated aqueous ion. State R is stabilised only after binding to a particular ligand. The most suitable conclusion is:

2. Assertion: Actinoid contraction arises from imperfect shielding by electrons.
Reason: Each added electron completely cancels the attraction of the additional proton.

3. Which statement most accurately describes oxidation states in the actinoid series?

4. A learner says that one dichromate ion accepts six electrons because its overall charge is . The most accurate correction is:

5. In a weak-field environment, is and is . Oxidation of to therefore:

6. A sample initially contains only a metal in oxidation state . It disproportionates completely so that equal numbers of metal atoms form oxidation states and . The average oxidation state of the metal after disproportionation is:

7. The correct identification of the two chromium(VI) oxoanions is:

8. The pair expected to have approximately the same spin-only magnetic moment of is:

9. A newly produced actinoid isotope decays so rapidly that only tiny amounts can be studied soon after its formation. Which inference is most reasonable?

10. A ion has four unpaired electrons in the simple Hund-rule picture. Using only as a spin-only estimate, select the value with the appropriate caution:

11. A group- metal forms ions in the and oxidation states. Their respective -electron configurations are:

12. A process requires permanganate to be reduced without forming either dissolved or a solid precipitate. The most suitable condition and product are:

13. A graph plots successive ionisation enthalpy on the vertical axis against electron-removal number on the horizontal axis for one transition metal. A very steep rise occurs between the second and third removals. This graph most strongly suggests that:

14. A standardised potassium permanganate solution is stored for a long time in a dirty bottle containing traces of reducing material. Its concentration is most likely to:

15. The data below compare melting point and enthalpy of atomisation for chromium, manganese, and iron.

The most reasonable interpretation of the manganese anomaly is:

16. As the oxidation state of a transition metal increases, the acid-base character of its oxides generally changes from:

17. Between two tripositive lanthanoid ions, ion P is larger than ion Q. Their hydroxides are compared under similar conditions. Which prediction is most reasonable?

18. The qualitative stability of half-filled and completely filled subshells is best interpreted by the statement:

19. Assertion: Some lanthanoids show relatively stable or oxidation states in addition to the dominant state.
Reason: Formation of , , or configurations can provide enhanced stability.

20. Using the spin-only relation

where is the number of unpaired electrons, the ratio is closest to:

21. Examine the oxidation-state information below.

The consistent rows are:

22. Pyrolusite, the manganese ore used in the preparation of potassium manganate, is mainly:

23. The Pauli exclusion principle places the following restriction on a single orbital:

24. A mixed vanadium oxide contains of vanadium atoms in the and oxidation states only. Its overall oxygen-to-vanadium atom ratio is . The amounts of and , respectively, are:

25. Absorption bands produced by - transitions in lanthanoid ions are commonly:

26. Use the orbital arrangement described below. The five orbitals are each singly occupied with parallel spins, while the orbital contains a pair of electrons. The atom represented is:

27. A compact electric motor requires a material with high coercivity and strong permanent magnetism. The most suitable material-function pairing is:

28. Assertion: Sulphuric acid is used in the conversion of sodium chromate into sodium dichromate.
Reason: It supplies hydrogen ions that favour condensation of chromate ions and also introduces sulphate into the sodium-salt products.

29. For ions of the same transition element in comparable coordination environments, increasing the positive oxidation state generally causes the ionic radius to:

30. A mixture contains only and . Chemical analysis shows that the mixture contains of copper. Using and , the amounts of and , respectively, are:

31. Manganese dioxide accelerates the decomposition:

Which observation is consistent with its catalytic role?

32. Complete reaction of of dichromate ions with excess iodide in acidic medium produces:

33. Transition elements commonly exhibit variable oxidation states because:

34. A laboratory requires an oxidant solution that can be prepared directly from an accurately weighed pure solid without first standardising the solution. The more suitable choice is:

35. The catalytic activity of many transition metals and their compounds is commonly linked to:

36. Use the periodic-table arrangement described below: a left block is followed by a central block and then a right block, while two long rows are printed separately beneath the table. The most suitable identification is:

37. A lanthanoid metal forms several compounds, but its oxidation state is observed far more frequently than its or states. The best explanation is:

38. Examine the oxidation-state and configuration data below.

The consistent rows are:

39. According to

the amount of required for complete conversion of of is:

40. Which atom is least likely to occupy an ordinary interstitial site in a transition-metal lattice because of its comparatively large size?

41. Potassium permanganate can act as a self-indicator in many acidic redox titrations because:

42. A group- transition element forms compounds in the , , and oxidation states. The number of electrons remaining in these states is respectively:

43. A graph of atomic radius against atomic number for the first transition series is expected to show:

44. A learner rejects the configuration because “the subshell must be completely filled before any electron can enter .” The best correction is:

45. Consider the following statements.
Statement I: Acidification shifts chromate toward orange dichromate.
Statement II: Strongly alkaline permanganate reduction to manganate is a one-electron process.
Statement III: Acidified dichromate accepts six electrons when reduced to .
Statement IV: Chromate, dichromate, and permanganate always have the same -factor.
The valid statements are:

46. An enthalpy-of-atomisation profile across a transition series shows a broad maximum near the middle and a much lower value for zinc. The most suitable interpretation is:

47. Moving from to and then to , the configurations change as:

48. Three hypothetical elements have the configurations shown below.

On the basis of the operational definition, the transition element is:

49. A learner claims that one mole of acidic permanganate oxidises five moles of iodine molecules because permanganate accepts five electrons. The best correction is:

50. During oxidation of to sodium chromate and iron(III) oxide, the changes in oxidation state are: