Class 12 Chemistry MCQ – Coordination Compounds

1. Which of the following terms is used for the ion or molecule bound directly to the metal atom?

a) Counter ion
b) Ligand
c) Chelate
d) Coordination entity

Answer:

b) Ligand

Explanation:

Ligands are ions or molecules that can donate pairs of electrons to the central metal atom or ion in a coordination compound.

2. Which of the following ligands can form a ring with the central metal atom?

a) Halide
b) Cyanide
c) Ethylenediamine
d) Ammonia

Answer:

c) Ethylenediamine

Explanation:

Ethylenediamine can form chelate rings with metal ions due to its bidentate nature.

3. How many coordination bonds are there in [Fe(CN)6]3−?

a) 3
b) 4
c) 6
d) 8

Answer:

c) 6

Explanation:

There are six cyanide ligands attached to the Fe ion, each forming one coordination bond.

4. What is the coordination number of Ni in [Ni(CO)4]?

a) 2
b) 4
c) 6
d) 8

Answer:

b) 4

Explanation:

There are four CO ligands attached to Ni, giving it a coordination number of 4.

5. Which of the following is a bidentate ligand?

a) NH3
b) H2O
c) Cl−
d) C2O4^2− (oxalate)

Answer:

d) C2O4^2− (oxalate)

Explanation:

The oxalate ion has two oxygen atoms that can bind to a central metal, making it a bidentate ligand.

6. What type of isomerism is exhibited by [Co(NH3)4Cl2]+ and [Co(NH3)2Cl4]2−?

a) Linkage isomerism
b) Ionization isomerism
c) Geometric isomerism
d) Optical isomerism

Answer:

b) Ionization isomerism

Explanation:

The two compounds give different ions in solution, demonstrating ionization isomerism.

7. The splitting of d-orbitals in an octahedral field is due to:

a) Presence of ligands
b) Shape of the coordination entity
c) Charge on the central metal ion
d) All of the above

Answer:

d) All of the above

Explanation:

The splitting of d-orbitals is influenced by the ligands, the geometry of the complex, and the charge on the metal ion.

8. Which of the following ligands is considered a strong field ligand?

a) Br−
b) F−
c) CN−
d) H2O

Answer:

c) CN−

Explanation:

Cyanide (CN−) is a strong field ligand and causes a large splitting of d-orbitals.

9. What is the oxidation number of Cr in [Cr(H2O)6]3+?

a) 0
b) +3
c) +6
d) −3

Answer:

b) +3

Explanation:

The oxidation number of Cr in [Cr(H2O)6]3+ is +3.

10. The coordination compounds having the same molecular formula but different properties are known as:

a) Resonance structures
b) Isomers
c) Isotones
d) Hybrids

Answer:

b) Isomers

Explanation:

Isomers are compounds with the same molecular formula but different structures or spatial arrangements, resulting in different properties.

11. A ligand that can ligate through two different atoms is known as:

a) Ambidentate
b) Bidentate
c) Polydentate
d) Monodentate

Answer:

a) Ambidentate

Explanation:

Ambidentate ligands can attach to the central metal atom through two different atoms.

12. Which compound will show optical isomerism?

a) [Co(NH3)4Cl2]+
b) [Co(NH3)6]3+
c) [Co(NH3)5Cl]2+
d) [Co(NH3)2Cl4]−

Answer:

a) [Co(NH3)4Cl2]+

Explanation:

[Co(NH3)4Cl2]+ can exist in two non-superimposable mirror image forms, hence it shows optical isomerism.

13. The color in coordination compounds arises due to:

a) Charge transfer transitions
b) d-d transitions
c) Ligand to metal charge transfer
d) All of the above

Answer:

d) All of the above

Explanation:

The color in coordination compounds can arise due to d-d transitions, charge transfer transitions, and ligand to metal charge transfers.

14. Which of the following ligands acts as a bridge between two metal centers?

a) H2O
b) NH3
c) CO
d) μ-OH

Answer:

d) μ-OH

Explanation:

μ-OH acts as a bridging ligand between two metal centers.

15. What type of hybridization is exhibited by [Ni(CO)4]?

a) sp
b) sp2
c) sp3
d) dsp2

Answer:

c) sp3

Explanation:

[Ni(CO)4] undergoes sp3 hybridization.

16. [Mn(H2O)6]3+ is colored, while [Sc(H2O)6]3+ is colorless. This is because:

a) Mn3+ has half-filled d-orbitals
b) Sc3+ has no unpaired electrons
c) Mn3+ undergoes d-d transitions
d) Both b and c

Answer:

d) Both b and c

Explanation:

Sc3+ has no unpaired electrons and doesn't undergo d-d transitions, whereas Mn3+ does, leading to the observed colors.

17. In Werner's theory, the number of ions produced by a coordination compound in an aqueous solution is termed as:

a) Coordination number
b) Oxidation number
c) Ionization number
d) Atomic number

Answer:

c) Ionization number

Explanation:

Werner introduced the idea of the ionization number, indicating the number of ions a compound would produce in solution.

18. Which ligand can cause a greater splitting of d-orbitals in an octahedral field?

a) H2O
b) NH3
c) Cl−
d) Br−

Answer:

b) NH3

Explanation:

Ammonia (NH3) is a stronger field ligand compared to the others listed and can cause greater d-orbital splitting.

19. The formula of a coordination compound is [Pt(NH3)2Cl4]. The pair of ions produced by this compound when dissolved in water is:

a) [Pt(NH3)2Cl2]2+ and 2Cl−
b) [Pt(NH3)4]2+ and 2Cl−
c) Pt4+ and [NH3Cl4]4−
d) [Pt(NH3)2Cl4] and 4OH−

Answer:

a) [Pt(NH3)2Cl2]2+ and 2Cl−

Explanation:

The compound produces [Pt(NH3)2Cl2]2+ and two chloride ions in solution.

20. Which of the following is a chelating ligand?

a) Cyanide
b) Chloride
c) Ammonia
d) Ethylenediamine

Answer:

d) Ethylenediamine

Explanation:

Ethylenediamine can form rings with metal ions due to its ability to bind at two sites, making it a chelating ligand.

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