Coordination Compounds Mock Test – Class 12 Chemistry

1. Match each industrial or catalytic application in Column I with the most appropriate coordination-chemistry feature in Column II.

2. Consider the following statements about limitations of simple valence bond theory.
Statement I: It does not quantitatively explain the colour of coordination compounds.
Statement II: It gives no satisfactory energetic account of why some complexes are high spin and others low spin.
Statement III: It does not calculate crystal-field stabilisation energy.
Statement IV: It cannot represent any coordination geometry.
The valid statements are:

3. In , the species enclosed by the coordination sphere is:

4. The cis form of can be optically active, whereas the standard trans form is achiral. The best structural explanation is that:

5. Under the standard valence bond treatment, is:

6. For , the first component named is:

7. Consider the following factors that can influence crystal field splitting.
Statement I: Identity of the ligand
Statement II: Oxidation state of the metal
Statement III: Metal–ligand distance
Statement IV: Coordination geometry
Which statements are correct?

8. Consider the following statements about .
Statement I: Its name is tetraammineplatinum(II) chloride.
Statement II: Platinum has oxidation state .
Statement III: The two chloride ions are named dichlorido because they are coordinated to platinum.
The valid statements are:

9. Assertion: A octahedral complex is called an inner-orbital complex.
Reason: The two orbitals used in hybridisation belong to the shell.

10. Assertion: Tetrahedral complexes are generally high spin.
Reason: is usually too small to overcome the pairing-energy cost.

11. Study the classification table.

The inconsistent row is:

12. A metal ion has a configuration. Under strong-field conditions, its electrons pair in three inner orbitals, leaving two inner orbitals vacant. The expected hybridisation, geometry, and number of unpaired electrons are:

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

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

15. Assertion: The cis form of an octahedral -type complex may show optical isomerism.
Reason: The arrangement of its two chelate rings can produce non-superimposable mirror-image structures.

16. Cisplatin and transplatin have the same formula, , but differ in:

17. The spin-only magnetic moment of a low-spin octahedral complex is approximately:

18. A measured spin-only moment near is obtained for an octahedral iron(III) complex. Which ligand and configuration best fit the observation?

19. If only the water of crystallisation is removed from , without changing the coordination sphere, the product is:

20. Consider the following statements.
Statement I: Coordination number counts directly bonded donor atoms.
Statement II: Oxidation state is obtained by algebraic charge balance.
Statement III: Coordination number must always equal the charge on the coordination entity.
Statement IV: The number of ligand particles may be smaller than the coordination number.
The valid statements are:

21. Match each metal ion in Column I with its -electron configuration in Column II.

22. The CFSE of low-spin , excluding pairing energy, is:

23. Assertion: Formation of a stable cyanido complex helps dissolve gold during metallurgical extraction.
Reason: Binding of oxidised gold by cyanide lowers its free concentration and favours continued conversion of metallic gold into soluble complex.

24. A coordination entity has the general formula , where every is neutral and every carries charge . The oxidation state of is:

25. A metal ion forms a square-planar complex after ligand-induced pairing. Which orbital arrangement permits hybridisation?

26. A student writes, “Because is assigned hybridisation, VBT has completely explained why cyanido produces a square-planar diamagnetic complex.” Which correction is most appropriate?

27. A ligand replacement shifts the main absorption of an octahedral complex from to . Which conclusion is most appropriate?

28. Relative to the barycentre, the energies per electron in the tetrahedral and sets are respectively:

29. 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:

30. Use the two arrangements described below.
Case 1: One ligand is bonded to two metal centres.
Case 2: One ligand uses both nitrogen atoms to bind the same metal centre.
The ligand roles in Case 1 and Case 2 are respectively:

31. Which statement correctly distinguishes CFSE from pairing energy?

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

33. The tetrahedral CFSE of a ion with configuration is:

34. The name of is:

35. If the positions of ligands around the same metal ion change from one coordination geometry to another, crystal field theory predicts that:

36. In , the ligand is chelating whereas the four ligands are not because:

37. A salt dissolves to give one bracketed ion and two ions per formula unit. No nitrate ligand appears inside the coordination sphere. The bracketed ion must:

38. Assertion: The numeral in pentaamminechloridocobalt(III) chloride is not the charge on the coordination entity.
Reason: One coordinated chlorido ligand lowers the charge of the cobalt(III) coordination entity from to .

39. Study the high-spin tetrahedral electron counts.

The inconsistent row is:

40. Select the valid description of :

41. A complex absorbs radiation of wavelength . Using and , the energy absorbed per photon is approximately:

42. Use the supplied complementary-colour table.

A complex that appears red predominantly absorbs:

43. For the cobalt(III) ammine series, let be the number of coordinated chloride ligands and be the moles of formed per mole of compound. The relation between and is:

44. In a confirmatory test, nickel(II) reacts with dimethylglyoxime in a suitable medium to produce:

45. Study the proposed consequences of increasing back-bonding.

The inconsistent row is:

46. Consider the following statements about the valence bond description of an octahedral complex.
Statement I: Six hybrid orbitals are required.
Statement II: Each ligand donor atom supplies one electron pair to a vacant hybrid orbital.
Statement III: Both and hybridisation can produce octahedral geometry.
Statement IV: Every octahedral complex must be diamagnetic.
The valid statements are:

47. A sample of is resolved into fractions and . Fraction rotates plane-polarised light clockwise, while produces an equal rotation in the opposite direction under identical conditions. The fractions are:

48. Assertion: The biological role of a coordination compound cannot be predicted from the identity of the metal alone.
Reason: The surrounding ligand framework controls geometry, electronic environment, binding sites, and chemical reactivity of the metal centre.

49. A coordination entity contains a metal in oxidation state , three neutral ligands, and one ligand formally treated as . Its overall charge is:

50. Study the proposed properties.

The inconsistent row is: