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

1. Which safety statement is most appropriate when comparing potassium dichromate and potassium permanganate?

2. Adjacent lanthanoids generally resemble one another chemically because they:

3. Acidified potassium permanganate is added to excess potassium iodide, followed by starch solution. Which observation is expected?

4. Assertion: Early actinoids generally show a wider range of oxidation states than later actinoids.
Reason: With increasing nuclear charge, the electrons become more tightly held and less readily available for bonding.

5. A graph plots the fraction of metal ions present as a ligand complex against increasing ligand concentration. Under otherwise identical conditions, the actinoid curve lies to the left of the corresponding lanthanoid curve. This most reasonably indicates that:

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

7. The sequence of highest oxidation states for , , , , and is:

8. Match the configuration fragment in Column I with the most suitable interpretation in Column II.

The appropriate matching is:

9. A learner says, “Because actinoid compounds show greater covalency, every actinoid compound must be a neutral molecular substance.” The best evaluation is:

10. The following standard reduction potentials are supplied.

The strongest reducing metal among X, Y, and Z is:

11. Acidified potassium permanganate is passed through a solution containing hydrogen sulphide. Which observation is most consistent with the redox reaction?

12. Some lanthanoid ions with complementary configurations and show related colours. The safest interpretation is:

13. Three ions , , and are isoelectronic and have nuclear charges increasing in the order . Their ionic radii are expected to follow:

14. Assertion: The variation in first ionisation enthalpy across a transition series is generally less dramatic than that across a typical main-group period.
Reason: Added electrons provide increasing shielding that partly offsets the rise in nuclear charge.

15. The initial decrease in atomic radii across a transition series is mainly caused by:

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

17. Two elements lie on opposite sides of manganese in the first transition series. Element X is an early member whose maximum oxidation state equals its group number, while element Y is a later member approaching a filled subshell. The more reasonable comparison is:

18. The following standard reduction potentials are supplied:


For the reaction

the value of and the predicted standard tendency are:

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

20. A student describes as “two chromate ions placed together without the loss or formation of any other species.” The best correction is:

21. Match each aqueous ion in Column I with its commonly observed colour in Column II.

The appropriate matching is:

22. Zinc, cadmium, and mercury often show lower melting points and softer behaviour than many central transition metals mainly because:

23. Consider the following statements about the transition series.
Statement I: The series occurs in period .
Statement II: The series occurs in period .
Statement III: The series occurs in period .
Statement IV: The series belongs to period and is incomplete.
The valid statements are:

24. Nickel promotes hydrogenation of an unsaturated compound mainly by:

25. Which ion is most likely to be colourless with respect to ordinary - transitions?

26. Acidified potassium dichromate is added to an excess of potassium iodide solution. Which observation is most consistent with the reaction?

27. Examine the oxidation-state information below.

The consistent rows are:

28. During the conversion

the oxidation state of chromium:

29. Which pair gives the orbital count and maximum electron capacity of an subshell?

30. An actinoid atom forms a ion, but its radioactive behaviour remains. This observation shows that:

31. Molybdenum is commonly represented by the ground-state configuration:

32. A student claims, “Because is common among actinoids, species such as and cannot exist.” The best evaluation is:

33. A set of radii for tripositive actinoid ions shows a gradual overall decrease as atomic number increases. The trend is identified as:

34. A lanthanoid ion is pale-coloured and paramagnetic. Which conclusion is most reasonable?

35. A transition metal forms a stable pentafluoride, but the corresponding simple aqueous ion is not observed. The most suitable conclusion is:

36. is effective in the oxidation of because vanadium can:

37. Match each ion in Column I with its -electron classification in Column II.

The appropriate matching is:

38. A student continues adding potassium permanganate after a stable faint pink colour has appeared in the titration flask. The most likely consequence is:

39. A student inserts fourteen additional positions into period after the element associated with group . These positions are intended to represent progressive filling of:

40. The colours of many tripositive lanthanoid ions arise mainly from:

41. An orbital arrangement beyond the core shows one electron in each of the five orbitals and one electron in the orbital. The corresponding compact electronic configuration is:

42. Use the graph description below. The vertical axis represents melting point and the horizontal axis runs across a transition series. Curve P rises toward a broad central high region and then falls irregularly near the end. Curve Q decreases smoothly from the first element to the last. Curve R remains horizontal, while Curve S has its only maximum at the end. The most realistic curve is:

43. Complete disproportionation of of according to

produces:

44. The set that represents the usual acidic reduction changes is:

45. Consider the following statements about configuration irregularities in later transition series.
Statement I: They may arise because the and subshells are close in energy.
Statement II: Every irregularity can be predicted by applying one universal half-filled-subshell rule.
Statement III: Supplied configuration data should be used when a later-series ground state is requested.
Statement IV: An configuration is possible for a -block atom.
The valid statements are:

46. Complete reaction of of permanganate with oxalate produces carbon dioxide. If the molar gas volume under the stated conditions is , the volume of formed is:

47. Match each species in Column I with its configuration in Column II.

The appropriate matching is:

48. A sample is represented by the average formula . The formula indicates that:

49. Consider the following redox changes.
P.
Q.
R.
The correct interpretation is:

50. A claim states, “The oxidation state of a transition-metal ion is always equal to the number of its remaining electrons.” The most suitable evaluation is: