Chemistry

Coordination Chemistry

325 Questions

Coordination chemistry focuses on coordination compounds, their structures, and their magnetic properties. The questions cover primary and secondary valencies, ligand types, and geometries of complexes. This topic is heavily tested in chemistry competitive exams and requires a good grasp of molecular structures.

primary and secondary valencycomplex geometriesligand field theorymagnetic properties of complexesisomerism in complexes

Coordination Chemistry Questions

Multiple choice

Which of the following complexes is not correctly named?

  1. Na3[Ag(S2O3)2]: Sodium bis(thiosulphato)argentite(I)

  3. [Pt(py)4][PtCl4]: Tetrapyridineplatinum(II)tetrachloroplatinate

  4. Li[AlH4]: Lithium tetrahydridoaluminate(III)

  5. [Zn(NCS)]2+: Tetrathiocyanato-N-zinc(II) cation
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Correct IUPAC name of [Fe(C5H5)2] is bis(cyclopentadienyl)iron(II).

Multiple choice

Which of the following substances show antiferromagnetism?

  1. Fe3O4

  2. MgFe2O4

  3. MnO

  4. CrO2

  5. NaCl
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Substances like MnO showing antiferromagnetism have domain structure similar to ferromagnetic substance, but their domains are oppositely oriented and cancel out each other's magnetic moment

Multiple choice

Which of the following sets contains only diamagnetic ions?

  1. Cu2+, Zn2+, Sc3+

  2. Zn2+, Sc3+, Ti4+

  3. Cu+, Mn2+, Cr3+

  4. Ni2+, Cu2+, Zn2+

  5. Cu+, Mn2+, Sc3+
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Zn2+: [Ar] 3d10 4s0; No unpaired electrons; diamagnetic Sc3+: [Ar] 3d0 4s0; No unpaired electrons; diamagnetic Ti4+: [Ar] 3d0 4s0; No unpaired electrons; diamagnetic

Multiple choice

Which of the following complexes cannot exhibit geometrical isomerism? i. [Ni(CN)4]2-
ii. [Zn(NH3)2Cl2] iii. [Pt(NH3)2Cl2]
iv. [Cr(NH3)6]3+

  1. i and ii only

  2. ii and iii only

  3. i, ii and iv only

  4. ii, iii and iv only

  5. iii and iv only
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

[Ni(CN)4]2- homoleptic complex with tetrahedral geometry. Homoleptic complex does not show geometrical isomerism. [Zn(NH3)2Cl2] is a heteroleptic complex with tetrahedral geometry. Tetrahedral complex does not exhibit geometrical isomerism, as all the four ligand positions are equivalent. [Pt(NH3)2Cl2] is a heteroleptic  square planar complex of Ma2b2 type. In a square planar complex of formula [Ma2b2], the two similar ligands may be arranged adjacent to each other in a cis isomer or opposite to each other in a trans isomer. [Co(NH3)6]3+homoleptic complex ion with octahedral geometry. Homoleptic complex does not show geometrical isomerism.

Multiple choice

Which of the following statements is false?

  1. Central metal atoms/ions in coordination complexes are Lewis acids.

  2. The secondary valency represents oxidation number of the central metal ion.

  3. Ligands are Lewis bases.

  4. Coordination number of cobalt in the compound [Co(ox)3]3- is 6.

  5. Oxidation number of cobalt in complex ion [CoCl2(en)2]+ is + 3.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The secondary valency represents coordination number of the central metal ion.

Multiple choice

Which of the following complexes have square planar geometry? i. [PtCl4]2- ii. [NiCl4]2- iii. [Pt(NH3)2Cl2] iv. [Ni(CO)4] v. [Ni(CN)4]2-

  1. i and ii only

  2. i, iii and iv only

  3. i, iii and v only

  4. ii, iv and v only

  5. iii and iv only
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

[PtCl4]2-: Inner orbital complex; square planar geometry; dsp2 hybridisation [Pt(NH3)2Cl2] -: Inner orbital complex; square planar geometry; dsp2 hybridisation [Ni(CN)4]2-: Inner orbital complex; square planar geometry; dsp2 hybridisation

Multiple choice

Which of the following ligands do not show linkage isomerism? (1) SO32-
(2) NO2-
(3) EDTA4-
(4) C2O42-
(5) SCN-

  1. 1 and 5 only

  2. 2 and 3 only

  3. 3 and 4 only

  4. 3, 4 and 5 only

  5. 2, 3 and 4 only
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Linkage isomerism is only shown by ambidentate ligands. EDTA4- (hexadentate ligand), is not a ambidentate ligand. Hence, it will not show linkage isomerism. C2O42- (bidentate ligand) is not a ambidentate ligand. Hence, it will not show linkage isomerism.