Coordination Compounds Quiz - ICSE Class 12 Chemistry

Free practice quiz: Coordination Compounds (ICSE Class 12 Chemistry). 61 multiple-choice questions with answers and explanations. Play online, no sign-up needed.

This ICSE Class 12 Chemistry practice quiz has 61 multiple-choice questions on Coordination Compounds, and 61 of them come with an explanation. Try the 5 sample questions below (tap an option to check yourself), then play the full quiz online. No sign-up needed.

Sample questions

1. Which of the following complexes exhibits the highest crystal field stabilization energy (CFSE) in an octahedral field?

   1. [Co(NH3)6]3+
   2. [Co(CN)6]3-
   3. [Co(H2O)6]3+
   4. [Co(en)3]3+
   Show answer

   Answer: B. [Co(CN)6]3-

   The crystal field stabilization energy (CFSE) depends on the spectrochemical series. CN- is a strong field ligand, NH3 and en are moderate field ligands, and H2O is a weak field ligand. Strong field ligands cause a larger splitting of d-orbitals (Δo), leading to higher CFSE. For d6 Co(III) complexes, the CFSE is -2.4 Δo for low spin and -0.4 Δo for high spin. [Co(CN)6]3- is a low spin complex with a strong ligand, resulting in the largest Δo and thus the highest CFSE.

2. A complex exhibits optical activity if it is chiral. Which of the following complexes is chiral?

   1. [Co(en)2Cl2]+
   2. [Co(NH3)4Cl2]+
   3. [Co(en)3]3+
   4. [Cr(NH3)6]3+
   Show answer

   Answer: A. [Co(en)2Cl2]+

   Chirality in coordination complexes often arises from the arrangement of ligands. For [Co(en)2Cl2]+, geometrical isomers exist: cis and trans. The cis isomer of [Co(en)2Cl2]+ is chiral and exists as a pair of enantiomers, hence it is optically active. The trans isomer has a plane of symmetry and is achiral. [Co(NH3)4Cl2]+ has cis and trans isomers, but neither is chiral. [Co(en)3]3+ and [Cr(NH3)6]3+ are octahedral complexes with all ligands identical or arranged symmetrically such that they possess planes of symmetry and are achiral.

3. Which of the following statements about coordination number is correct?

   1. It is always equal to the number of ligands.
   2. It is the number of ions surrounding the central metal ion.
   3. It is the number of direct coordinate bonds formed by the central metal ion with ligands.
   4. It is equal to the oxidation state of the central metal ion.
   Show answer

   Answer: C. It is the number of direct coordinate bonds formed by the central metal ion with ligands.

   The coordination number of a central metal ion in a complex is defined as the number of sigma bonds formed between the central metal ion and the ligands. It is not necessarily equal to the number of ligands (as polydentate ligands count differently) or the number of ions surrounding it. It is also distinct from the oxidation state.

4. The oxidation state of nickel in K2[Ni(CN)4] is:

   1. 0
   2. +1
   3. +2
   4. +4
   Show answer

   Answer: C. +2

   Let the oxidation state of Nickel be x. The complex is neutral, so the sum of oxidation states is zero. 2(+1) (for K) + x (for Ni) + 4(-1) (for CN) = 0 => 2 + x - 4 = 0 => x - 2 = 0 => x = +2. Therefore, the oxidation state of Nickel is +2.

5. What is the correct IUPAC name for Na[AuCl4]?

   1. Sodium tetrachloroaurate(III)
   2. Sodium tetrachlorogold(III)
   3. Sodium tetrachloroaurate(I)
   4. Gold sodium tetrachloride
   Show answer

   Answer: A. Sodium tetrachloroaurate(III)

   The cation is sodium (Na+). The complex anion is [AuCl4]-. The metal is gold, and in anionic complexes, it is called 'aurate'. The ligands are chloro. There are four chloro ligands, hence 'tetrachloro'. To find the oxidation state of Au: +1 (for Na) + x (for Au) + 4(-1) (for Cl) = 0 => 1 + x - 4 = 0 => x = +3. So, the name is Sodium tetrachloroaurate(III). 'Gold' is used for cationic complexes, 'aurate' for anionic.

More questions in this quiz

Answers and explanations are in the full quiz.

1. The complex [Ni(dmgH)2] (dmgH = dimethylglyoxime) is a square planar complex. What is the hybridization of the central Ni atom?
2. What is the correct IUPAC name for the complex K4[Fe(CN)6]?
3. Which of the following ligands can exhibit both sigma and pi bonding interactions with the central metal ion?
4. The magnetic moment of a complex is found to be 5.92 BM. What is the likely number of unpaired electrons in the central metal ion?
5. When an aqueous solution of CoCl3.5NH3 reacts with AgNO3, it gives 1 mole of AgCl precipitate. The structure of the complex is:
6. Which of the following is an example of a bidentate ligand?
7. The color of transition metal complexes is primarily due to:
8. What is the oxidation state of Cobalt in the complex [Co(NH3)4Cl2]+?
9. Which of the following is NOT a type of isomerism found in coordination compounds?
10. The effective atomic number (EAN) of the central metal atom in the complex [Ni(CO)4] is:
11. Which of the following statements about Werner's theory of coordination compounds is INCORRECT?
12. A complex salt on treatment with H2S gives a black precipitate. The complex contains which metal ion?
13. Which of the following complexes is diamagnetic?
14. The trans isomer of [Co(en)2Cl2]+ is:
15. Which of the following factors affects the magnitude of crystal field splitting (Δo) in an octahedral complex?
16. The complex [Cr(NH3)3Cl3] exists in two isomeric forms. These isomers are:
17. What is the number of donor atoms in a tridentate ligand?
18. Which of the following is an example of linkage isomerism?
19. What is the magnetic moment of [Fe(H2O)6]2+ if Δo > P (pairing energy)?
20. The complex [Pt(NH3)2Cl2] exhibits isomerism. What type of isomerism is it?
21. In which of the following complexes does the metal ion exhibit a +1 oxidation state?
22. The ligand that forms a chelate ring is:
23. The IUPAC name for [Co(NH3)4Cl2]+ is:
24. Which of the following is an example of a homoleptic complex?
25. The complex diamminedichloroplatinum(II) is an example of:
26. Which property of coordination compounds is explained by the Ligand Field Theory?
27. What is the number of unpaired electrons in the Fe(II) ion in a high-spin octahedral complex?
28. Which type of isomerism is exhibited by [Co(NH3)5Br]SO4 and [Co(NH3)5SO4]Br?
29. What is the correct IUPAC name for [Cr(NH3)4Cl2]Cl?
30. Which of the following is a chelating agent?
31. The stability of coordination compounds is often measured by:
32. What is the coordination number of the central metal ion in [Co(en)2(NH3)2]3+?
33. Which of the following ligands is ambidentate?
34. In the complex [Fe(CO)5], the hybridization of the central iron atom is:
35. The magnetic moment of [Mn(H2O)6]2+ is approximately 5.9 BM. This suggests that the complex is:
36. Which of the following statements about cis-trans isomerism in square planar complexes is true?
37. The phenomenon of 'chelate effect' leads to:
38. What is the correct IUPAC name for [Pt(en)2]Cl2?
39. Which metal ion is central in the formation of Vitamin B12?
40. The spectrochemical series is an empirical ordering of ligands based on their ability to cause crystal field splitting. Which of the following is arranged in the correct order of increasing ligand field strength?
41. What is the oxidation state of copper in the complex [Cu(NH3)4]SO4?
42. The cis isomer of [MA2B2] type complex exhibits:
43. Which of the following is the most stable complex?
44. The colour of [Cu(H2O)6]2+ is blue. If ammonia is added, the solution turns deep blue. This is due to the formation of:
45. Which of the following is an example of a neutral complex?
46. The spin-only magnetic moment of [Co(NH3)6]3+ is 0 BM. This indicates that the complex is:
47. Which phenomenon explains the difference in color between [Fe(H2O)6]3+ (pale violet) and [FeF6]3- (pale green)?
48. The complex [Cr(en)3]3+ is:
49. What is the charge on the complex ion [Ni(CN)4]?
50. The IUPAC name for [Cr(NH3)3Cl3] is:
51. Which of the following coordination compounds is likely to be colored?
52. The magnetic moment of a complex is measured to be 2.83 BM. This corresponds to the presence of how many unpaired electrons?
53. Which of the following is a correct representation of a Werner's primary valency in a complex?
54. The complex [Cr(NH3)3Cl3] can exist in two forms which are geometrical isomers. These forms are called:
55. What is the role of the central metal atom in a coordination compound?
56. The ligand that is also a functional group in organic chemistry and can act as a monodentate or bridging ligand is:

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