Coordination Compounds Mock Test – Class 12 Chemistry

1. An octahedral entity of type has only one geometrical arrangement because:

2. An iron atom has the ground-state configuration . The -electron configuration of is:

3. For the stepwise formation equilibrium

the constant measures:

4. Study the proposed octahedral CFSE values.

The inconsistent row is:

5. The usual valence bond reasoning for a strong-field octahedral complex follows the sequence:

6. Three statements describe how denticity affects coordination. Identify the valid combination.
Statement I: An ambidentate ligand may possess two potential donor atoms.
Statement II: A bidentate ligand normally uses two donor atoms simultaneously to bind one metal centre.
Statement III: Each ambidentate ligand necessarily contributes to the coordination number.
The valid statements are:

7. Study the charge-balance table.

The inconsistent row is:

8. An octahedral ion has the configuration . Its CFSE is:

9. Consider the following statements about coordination nomenclature.
Statement I: The bracketed coordination entity is named as one unit.
Statement II: The oxidation state of the central metal is written using a Roman numeral.
Statement III: Counter ions are always omitted from the complete compound name.
The valid statements are:

10. Carbon monoxide forms strong complexes with metals in low oxidation states and participates in metal-to-ligand back-bonding. Why is this behaviour not fully described by elementary crystal field theory?

11. The ligand names for , , , and , in that order, are:

12. A student analyses and writes, “Manganese has oxidation state , so the complex has unpaired electrons.” Which correction is most appropriate?

13. In valence bond theory, hybridisation of the central metal orbitals is mainly used to explain:

14. Why are the octahedral orbital-energy coefficients and , rather than equal values?

15. A graph for an octahedral complex shows increasing along the horizontal axis. What magnetic change is expected as the system moves from to ?

16. Study the octahedral arrangements.

The inconsistent row is:

17. Assign the IUPAC name to :

18. Electron pairing may occur before hybridisation primarily to:

19. A graph has absorbed wavelength on the horizontal axis and crystal-field splitting on the vertical axis. Which curve best represents the relation between them?

20. A proposed name for contains cobalt(II). The most accurate diagnosis is:

21. An octahedral complex of the type can show:

22. The naming order of differs from that of because:

23. A metal ion is initially surrounded by six separate monodentate ligands. They are replaced by one ligand, and all six donor atoms of bind to the metal. The replacement changes:

24. Two colourless crystalline solids and are dissolved separately. Every simple ion expected from the constituent salts of can be detected independently. In the solution of , one bracketed metal–ligand ion remains the principal metal-containing species. The sound conclusion is:

25. A theory predicts that a complex is octahedral and paramagnetic but cannot account satisfactorily for its absorption wavelength. The theory being used is most likely:

26. Study the proposed classifications.

The inconsistent row is:

27. Assertion: donation and back-bonding in a metal carbonyl reinforce one another.
Reason: donation increases electron density at the metal for back donation, while back donation removes some metal electron density and allows continued ligand-to-metal donation.

28. A tetrahedral ion has configuration . Which set of properties is correct?

29. The pair and differs because:

30. In , the coordination sphere contains:

31. A student says, “The colour is an unchanging property of the metal ion, so every complex containing that ion must have the same colour.” The best correction is:

32. A four-coordinate complex is experimentally diamagnetic. Another complex of the same metal ion is paramagnetic with two unpaired electrons. The most consistent geometries of the two complexes are respectively:

33. Choose the IUPAC name for :

34. Study the proposed magnetic-property assignments.

The inconsistent row is:

35. Complexes and contain the same metal ion in the same oxidation state and have the same geometry. The ligand in produces a stronger field than the ligand in . Which conclusion is most reasonable?

36. Crystal field theory differs from simple valence bond theory because:

37. Assertion: Outer-orbital octahedral complexes commonly have more unpaired electrons than corresponding paired inner-orbital complexes of the same ion.
Reason: Formation of hybrid orbitals does not require two vacant inner orbitals.

38. Consider the following statements about coordination catalysts.
Statement I: A substrate may bind temporarily to the metal centre.
Statement II: Coordination can orient reacting molecules favourably.
Statement III: A catalyst must be permanently converted into the final product.
Statement IV: Ligand substitution may create a vacant site for substrate binding.
The valid statements are:

39. A member of the cobalt(III) ammine series has the general formula

where may have values from to . The total number of dissolved species produced per formula unit on ideal dissolution is:

40. Two ligands in an octahedral entity are replaced by one ethane-1,2-diamine ligand, represented by , without changing the coordination number. The resulting formula and total number of ligand molecules are:

41. Assertion: In the name of , the coordination entity is named before chloride.
Reason: The bracketed entity is a cation, and a cation is named before an anion.

42. Study the ligand-name table.

The inconsistent row is:

43. In the equilibrium

why is formation of the chelate complex often favoured?

44. The platinum centre in cisplatin follows the sequence:

45. Use the arrangement described below: structure and structure are mirror images. No rotation or translation can make every ligand position in coincide with the corresponding position in . The pair represents:

46. Study the oxidation-state assignments below.

The inconsistent row is:

47. Separate aqueous solutions of Mohr’s salt and are treated with a reagent that tests for free . The expected observation is that:

48. Which observation correctly identifies cis-?

49. Complexes and both have the form and are compared under the same conditions. Their overall formation constants are and . Which conclusion is justified?

50. In , the oxidation states of cobalt and chromium are: