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

Among the following the more stable complexes of thalium is/are

P. Tl(OH) Q. TlCl3 R. TlBr S. TlN3

  1. P only

  2. Q only

  3. R only

  4. P and Q

  5. Q and R
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Thallium tends to oxidize to the +3 and +1 oxidation states as ionic salts. The +3 state resembles that of the other elements in thallium's group (boron, aluminum, gallium, indium). Thallium represents +1 oxidation state due to the inert pair effect. Hence, Tl(OH) and TlBr are more stable complexes than TlN3 and TlCl3.

Multiple choice

Which of the following pairs is not correctly matched?

  1. Ethylene diaminetetraacetate ion: Hexadentate ligand

  2. Chemotherapy of cancer: cis-[PtII (NH3)2 Cl2]

  3. Cyanate ion: Ambidentate ligand

  4. Nitrite ion: Bidentate ligand

  5. Pentaamminechloridocobalt(III) sulphate: [Co(NH3)5Cl]SO4
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The nitrite ion (NO2-) is an ambidentate ligand and can bind to metal ions through either the nitrogen or oxygen atom.

Multiple choice

In molecular ion ICl2+, the geometrical arrangement of orbital and shape are

  1. tetrahedral geometry, bent shape

  2. tetrahedral geometry, pyramidal shape

  3. trigonal bipyramidal geometry, linear shape

  4. trigonal bipyramidal geometry, bent shape

  5. tetrahedral geometry, T-shape
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

ICl2+ has sp3 hybridisation and its geometrical arrangement of orbitals is tetrahedral but the shape (according to VESPR theory) is bent due to the presence of two lone pairs. Thus, this option is correct.

Multiple choice

Which of the following statements is FALSE?

  1. Compounds of copper (II) are coloured but those of zinc (II) are colourless.

  2. Pt(IV) complexes are octahedral while Pt(II) complexes are square planar.

  3. Mn(II) ion show maximum paramagnetic character amongst bivalent ions of first transition series.

  4. Zinc metal is diamagnetic while Zn2+ ion is paramagnetic.

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

Correct answer. Zn: [Ar] 3d10 4s2 Zn2+: [Ar] 3d10 In zinc metal and Zn2+, all electrons are paired and hence they both are diamagnetic.

Multiple choice

Match the Column I molecules/molecular ions with Column II bond orders and Column III magnetic properties:

   
Molecular ion
Bond order
Magnetic character
(i) H2+ a. 2.5 x. Paramagnetic
(ii) C2 b. 3.0 y. Diamagnetic
(iii) CN- c. 0.5
(iv) O2- d. 1.0
(v) NO e. 2.0
(vi) F2 f. 1.5

  1. i - a - y, ii - d - x, iii - b - x, iv - c - y, v - f - x, vi - e - y

  2. i - e - y, ii - c - x, iii - f - x, iv - b - y, v - a - x, vi - d - y

  3. i - c - y, ii - e - x, iii - b - x, iv - f - y, v - a - y, vi - d - x

  4. i - a - x, ii - d - y, iii - b - y, iv - c - x, v - f - y, vi - e - x

  5. i - c - x, ii - e - y, iii - b - y, iv - f - x, v - a - x, vi - d - y
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

This option is correct because all the molecular ions are correctly matched with their bond order and magnetic properties. According to molecular orbital energy level diagram: for example of energy levels of molecular orbitals of O2- : σ1s2, σ*1s2, σ2s2, σ*2s2, σ2pz2, π2p x 2=π2py2, π*2px2=π*2py1 Bond order = 1/2 (number of bonding electrons-number of antibonding electrons) = 1/2 (10-7) = 1.5 And due to the presence unpaired electron in π*2py1 molecular orbital, this molecule is paramagnetic.