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 compounds shows MLCT transfer?

  1. HgO

  2. CdS

  3. Pb3(SbO4)2

  4. [Ru(2, 2bipyridyl)3]

  5. None of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

This option is correct because the compound [Ru (2, 2 bipyridyl) 3] shows MLCT due to the metal electron transfer to the pi antibonding molecular orbital of ligand. It is produced orange in colour.

Multiple choice

How many doublet state are possible in [Mn(H2O)6]++ complexes?

  1. 7

  2. 11

  3. 5

  4. 3

  5. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

This option is correct because the central metal atom of the complexes belong to the 3d5 configuration, which is correlated to ground state term of S6. These terms are split in to 11 excited states from which 4 is quartets excited and remaining 7 is doublet excited.

Multiple choice

The zero magnetic moment of octahedral complexes K2NiF6 is due to

  1. low spin 3d6 Ni (IV) complex

  2. low spin 3d8 Ni(II) complex

  3. high spin 3d8 Ni(II) complex

  4. high spin 3d6 Ni (IV) complex

  5. none of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

This option is correct because the K2NiF6 shows the high spin character but actually cannot exhibit zero magnetic moment. Hence, these complexes behave as low spin in nature, the electrons are distributed in 6t2g and 0eg due to distribution of electron. No unpaired electron occur, i.e. magnetic moment is zero in low spin.

Multiple choice

Which of the following complexes X, Y and Z is/are inert or labile? (X) [V(NH3)6]+++ (Y) = [Co(CN)6]3- (Z) = [Cr(CN)6]3-

  1. X and Y are inert, Z is labile.

  2. X and Z are labile, Y is inert.

  3. X is inert, Y and Z are labile.

  4. X is labile, Y and Z are inert.

  5. None of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

This option is correct, because the complex  X is labile, they contain the unhybridised metal orbital through which the ligand is attached more quickly in this orbital. But Y and Z are inert due to lack of availability unhybridised metal orbital the ligand cannot be attached in this orbital. (Lability shows more fast reaction and inert shows slow  reaction).

Multiple choice

The compound, which exhibits Jahn-Teller distortion is __________.

  1. [Mn(H2O)6]2+

  2. [Mn(H2O)6]3+

  3. [Cr(H2O)6]3+

  4. [Fe(CN)6]4-

  5. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

This option is correct, because the [Mn(H2O)6]3+ compound is high spin compound. It is related to the 3d4 configuration and splits into 3t2g symmetrical and 1eg unsymmetrical, which exhibit the strong Jahn – Teller distortion.

Multiple choice

The treatment of [PtCl4]2- with two equivalent of NH3 ligand leads to the formation of [Pt(NH3)2Cl2]. The complex is

  1. Trans [PtCl2(NH3)2], due to stronger trans effect of Cl- compared to NH3.

  2. Trans [PtCl2(NH3)2], due to weaker trans effect of Cl- compared to NH3.

  3. Cis [PtCl2(NH3)2], due to weaker trans effect of Cl- compared NH3.

  4. Cis [PtCl2(NH3)2], due to stronger trans effect of Cl- compared to NH3.

  5. None of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

This option is correct  because the Cis [Pt(NH3)2Cl2] complex ions is formed when [Pt(Cl)4]2-react with NH3 to form [Pt(NH3)(Cl)3]- and again it reacts with NH3 to form Cis [Pt(Cl)2(NH3)2] complex, due to the stronger effect Cl- than NH3.

Multiple choice

The number of absorption band observed in [Co(H2O)6]2+ and [CoF6]3- respectively are ________.

  1. 1 and 3

  2. 0 and 1

  3. 0 and 3

  4. 3 and 1

  5. None of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

This option is correct because [Co(H2O)6]2+ complexes ion in Co2+ are related to 3d7 electronic configuration and have F4 ground state term. It splits in to 4T1g(F),4T2g(F), 4A2g(F) and 4T1g(P), respectively, i.e. show 3 bands but other complexes ion spin allowed transition in 5T2g and 5Eg one absorption band.

Multiple choice

Which of the following statements is correct?

  1. O2- is diamagnetic.

  2. N2 and CN- are isoelectronic and chemically inert.

  3. NO3- and CO32- are isostructural.

  4. CO2 is a bent molecule.

  5. CO and NO+ are isoelectronic.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Both NO3- and CO32- have 32 electrons with sp2 hybridised central atom and trigonal planar geometry.

Multiple choice

Identify the correct statement.

  1. [PtCl4]2- has square planar geometry.

  2. [Fe(CN)6]4- is inner orbital complex while [Ni(NH3)6]2+ is outer orbital complex.

  3. Fe2O3 and CuO are amphoteric oxides.

  4. TiF2 has linear shape.

  5. Solution containing Cu+ ion is blue coloured.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

[Fe(CN)6]4-: d2sp3 hybridisation and inner orbital complex [Ni(NH3)6]2+: sp3d2 hybridisation and outer orbital complex Hence, [Fe(CN)6]4- inner orbital complex and [Ni(NH3)6]2+ outer orbital complex.