Coordination Chemistry Mcqs

Coordination Chemistry MCQs

1. What is a metal complex?

• a) A metal bonded to another metal
• b) A central metal atom bonded to a group of molecules or ions
• c) A metal bonded to a non-metal
• d) A metal bonded to a gas

2. What is a complex ion?

• a) A neutral complex
• b) A charged complex
• c) A complex with no ligands
• d) A complex with only water ligands

3. What are ligands?

• a) Molecules or ions that bond to a central metal atom
• b) Only anions that bond to metals
• c) Only polar molecules that bond to metals
• d) Molecules that do not bond to metals

4. Which of the following is NOT a ligand?

• a) NH₃
• b) Cl⁻
• c) H₂O
• d) Na⁺

5. What is the coordination number of Co(III) in [Co(NH₃)₆]Cl₃?

• a) 3
• b) 4
• c) 5
• d) 6

6. According to Werner’s theory, what is the primary valence of a metal ion?

• a) The number of ligands bonded to the metal
• b) The oxidation number of the metal
• c) The charge on the complex ion
• d) The number of atoms in the coordination sphere

7. What is the secondary valence in Werner’s theory?

• a) The oxidation number of the metal
• b) The number of atoms directly bonded to the metal (coordination number)
• c) The charge on the complex ion
• d) The number of free ions in the solution

8. Which of the following complexes is green in color?

• a) [Co(NH₃)₆]Cl₃
• b) [Co(NH₃)₅Cl]Cl₂
• c) trans-[Co(NH₃)₄Cl₂]Cl
• d) cis-[Co(NH₃)₄Cl₂]Cl

9. What is the modern formulation of CoCl₃·6NH₃?

• a) [Co(NH₃)₆]Cl₃
• b) [Co(NH₃)₅Cl]Cl₂
• c) [Co(NH₃)₄Cl₂]Cl
• d) [Co(NH₃)₃Cl₃]

10. What is the coordination sphere in a complex?

• a) The central metal and the ligands directly bonded to it
• b) The free ions in the solution
• c) The ligands outside the coordination sphere
• d) The solvent molecules

11. Which of the following is a bidentate ligand?

• a) NH₃
• b) H₂O
• c) en (ethylenediamine)
• d) Cl⁻

12. What is the name of the ligand EDTA?

• a) Ethylenediaminetetraacetate
• b) Ethylenediaminetriacetate
• c) Ethylenediaminediacetate
• d) Ethylenediamine

13. What is the oxidation number of Cu in [Cu(NH₃)₄]²⁺?

• a) +1
• b) +2
• c) +3
• d) +4

14. What is the charge on the complex ion [Cr(H₂O)₄Cl₂]?

• a) +1
• b) +2
• c) +3
• d) 0

15. Which of the following is a polydentate ligand?

• a) NH₃
• b) H₂O
• c) EDTA
• d) Cl⁻

16. What is the coordination number of Cr(III) in [Cr(H₂O)₆]³⁺?

• a) 4
• b) 5
• c) 6
• d) 7

17. Which of the following is a square planar complex?

• a) [Co(NH₃)₆]³⁺
• b) [Pt(NH₃)₂Cl₂]
• c) [Fe(CN)₆]⁴⁻
• d) [Ni(CO)₄]

18. What is the name of the complex [Co(NH₃)₅Cl]Cl₂?

• a) Pentaamminechlorocobalt(III) chloride
• b) Pentachlorocobalt(III) ammine
• c) Pentaamminecobalt(III) chloride
• d) Chloropentaamminecobalt(III) chloride

19. Which of the following is an example of a linkage isomer?

• a) [Co(NH₃)₅NO₂]²⁺
• b) [Co(NH₃)₅Cl]²⁺
• c) [Co(NH₃)₆]³⁺
• d) [Co(en)₃]³⁺

20. What is the color of [Ti(H₂O)₆]³⁺?

• a) Green
• b) Purple
• c) Yellow
• d) Blue

21. Which of the following ligands is the strongest field ligand?

• a) Cl⁻
• b) H₂O
• c) NH₃
• d) CN⁻

22. What is the spectrochemical series?

• a) A series of metals arranged by their reactivity
• b) A series of ligands arranged by their strength of interaction with metal ions
• c) A series of complexes arranged by their color
• d) A series of coordination numbers

23. What is the splitting of d-orbitals in an octahedral field called?

• a) Crystal field splitting
• b) Ligand field splitting
• c) Molecular orbital splitting
• d) Hybridization

24. Which of the following is a high-spin complex?

• a) [Co(CN)₆]³⁻
• b) [CoF₆]³⁻
• c) [Co(NH₃)₆]³⁺
• d) [Co(en)₃]³⁺

25. What is the geometry of [Ni(CO)₄]?

• a) Tetrahedral
• b) Square planar
• c) Octahedral
• d) Linear

26. Which of the following is an example of a geometric isomer?

• a) [Co(NH₃)₅Cl]²⁺
• b) [Pt(NH₃)₂Cl₂]
• c) [Co(en)₃]³⁺
• d) [Fe(CN)₆]⁴⁻

27. What is the name of the complex [Cr(H₂O)₄Cl₂]Cl?

• a) Tetrachlorodiaquachromium(III) chloride
• b) Dichlorotetraaquachromium(III) chloride
• c) Tetraaquadichlorochromium(III) chloride
• d) Dichlorotetraaquachromium(II) chloride

28. Which of the following is an example of an optical isomer?

• a) [Co(NH₃)₅Cl]²⁺
• b) [Co(en)₃]³⁺
• c) [Pt(NH₃)₂Cl₂]
• d) [Fe(CN)₆]⁴⁻

29. What is the color of [Cr(H₂O)₆]³⁺?

• a) Green
• b) Violet
• c) Yellow
• d) Blue

30. Which of the following is a low-spin complex?

• a) [CoF₆]³⁻
• b) [Co(CN)₆]³⁻
• c) [Co(H₂O)₆]³⁺
• d) [Co(NH₃)₆]³⁺

31. What is the name of the complex [Co(NH₃)₄Cl₂]Cl?

• a) Tetraamminedichlorocobalt(III) chloride
• b) Dichlorotetraamminecobalt(III) chloride
• c) Tetraamminecobalt(III) dichloride
• d) Dichlorotetraamminecobalt(II) chloride

32. Which of the following is a chelating agent?

• a) NH₃
• b) H₂O
• c) EDTA
• d) Cl⁻

33. What is the oxidation number of Cr in [Cr(H₂O)₄Cl₂]Cl?

• a) +1
• b) +2
• c) +3
• d) +4

34. Which of the following is a tetradentate ligand?

• a) NH₃
• b) en (ethylenediamine)
• c) EDTA
• d) Cl⁻

35. What is the color of [Cr(CN)₆]³⁻?

• a) Green
• b) Violet
• c) Yellow
• d) Blue

36. Which of the following is a high-spin complex?

• a) [Co(CN)₆]³⁻
• b) [CoF₆]³⁻
• c) [Co(NH₃)₆]³⁺
• d) [Co(en)₃]³⁺

37. What is the geometry of [Pt(NH₃)₂Cl₂]?

• a) Tetrahedral
• b) Square planar
• c) Octahedral
• d) Linear

38. Which of the following is an example of a coordination-sphere isomer?

• a) [Co(NH₃)₅Cl]Cl₂
• b) [Co(NH₃)₅NO₂]Cl₂
• c) [Co(NH₃)₆]Cl₃
• d) [Co(en)₃]Cl₃

39. What is the name of the complex [Co(NH₃)₅NO₂]Cl₂?

• a) Pentaamminechlorocobalt(III) chloride
• b) Pentaamminecobalt(III) nitrite chloride
• c) Pentaamminecobalt(III) nitro chloride
• d) Pentaamminecobalt(III) nitrito chloride

40. Which of the following is a low-spin complex?

• a) [CoF₆]³⁻
• b) [Co(CN)₆]³⁻
• c) [Co(H₂O)₆]³⁺
• d) [Co(NH₃)₆]³⁺

41. What is the color of [CrF₆]³⁻?

• a) Green
• b) Violet
• c) Yellow
• d) Blue

42. Which of the following is a high-spin complex?

• a) [Co(CN)₆]³⁻
• b) [CoF₆]³⁻
• c) [Co(NH₃)₆]³⁺
• d) [Co(en)₃]³⁺

43. What is the geometry of [Ni(CO)₄]?

• a) Tetrahedral
• b) Square planar
• c) Octahedral
• d) Linear

44. Which of the following is an example of a geometric isomer?

• a) [Co(NH₃)₅Cl]²⁺
• b) [Pt(NH₃)₂Cl₂]
• c) [Co(en)₃]³⁺
• d) [Fe(CN)₆]⁴⁻

45. What is the name of the complex [Cr(H₂O)₄Cl₂]Cl?

• a) Tetrachlorodiaquachromium(III) chloride
• b) Dichlorotetraaquachromium(III) chloride
• c) Tetraaquadichlorochromium(III) chloride
• d) Dichlorotetraaquachromium(II) chloride

46. Which of the following is an example of an optical isomer?

• a) [Co(NH₃)₅Cl]²⁺
• b) [Co(en)₃]³⁺
• c) [Pt(NH₃)₂Cl₂]
• d) [Fe(CN)₆]⁴⁻

47. What is the color of [Cr(H₂O)₆]³⁺?

• a) Green
• b) Violet
• c) Yellow
• d) Blue

48. Which of the following is a low-spin complex?

• a) [CoF₆]³⁻
• b) [Co(CN)₆]³⁻
• c) [Co(H₂O)₆]³⁺
• d) [Co(NH₃)₆]³⁺

49. What is the name of the complex [Co(NH₃)₄Cl₂]Cl?

• a) Tetraamminedichlorocobalt(III) chloride
• b) Dichlorotetraamminecobalt(III) chloride
• c) Tetraamminecobalt(III) dichloride
• d) Dichlorotetraamminecobalt(II) chloride

50. Which of the following is a chelating agent?

• a) NH₃
• b) H₂O
• c) EDTA
• d) Cl⁻