COORDINATION COMPOUNDS - 20 NEET MCQs

Coordination Compounds - NEET Level MCQs

1. The coordination number of Co in [Co(NH₃)₆]Cl₃ is:
   a) 3
   b) 4
   c) 5
   d) 6


2. The oxidation state of Co in [Co(en)₂Cl₂]⁺ is:
   a) +1
   b) +2
   c) +3
   d) 0


3. The ligand which can form more than one coordinate bond is called:
   a) Monodentate
   b) Bidentate
   c) Polydentate
   d) Ambidentate


4. Which of the following is an ambidentate ligand?
   a) NH₃
   b) CN⁻
   c) NO₂⁻
   d) en


5. The number of geometrical isomers possible for [Pt(NH₃)₂Cl₂] is:
   a) 1
   b) 2
   c) 3
   d) 4


6. Which of the following complexes will exhibit optical isomerism?
   a) [Co(NH₃)₆]³⁺
   b) [Co(en)₃]³⁺
   c) [PtCl₄]²⁻
   d) [Ni(CN)₄]²⁻


7. Which of the following is a chelating ligand?
   a) NH₃
   b) H₂O
   c) en
   d) Cl⁻


8. In [Fe(CN)₆]⁴⁻, the magnetic moment is:
   a) 0 BM
   b) 1.73 BM
   c) 5.92 BM
   d) 2.83 BM


9. Which of the following complexes will show linkage isomerism?
   a) [Co(NH₃)₆]³⁺
   b) [Co(NO₂)(NH₃)₅]²⁺
   c) [Fe(CN)₆]³⁻
   d) [Ni(CO)₄]


10. The hybridization of Ni in [Ni(CO)₄] is:
    a) sp
    b) sp²
    c) sp³
    d) dsp²


11. The color of coordination compounds is due to:
    a) Ionization
    b) d–d transitions
    c) s–p transitions
    d) Crystal field splitting


12. Which rule helps to determine the geometry of complexes based on pairing of electrons?
    a) Crystal Field Theory
    b) Valence Bond Theory
    c) Molecular Orbital Theory
    d) Hybridization theory


13. The IUPAC name of [Cr(H₂O)₄Cl₂]Cl is:
    a) Tetraaquadichlorochromium(III) chloride
    b) Dichlorotetraaquachromium(III) chloride
    c) Chromium tetraaquadichloride
    d) Chromium(II) tetraaquadichloride


14. Which of the following has square planar geometry?
    a) [Ni(CN)₄]²⁻
    b) [NiCl₄]²⁻
    c) [CoCl₄]²⁻
    d) [Zn(NH₃)₄]²⁺


15. Which of the following statements is true about [Fe(CN)₆]³⁻ and [FeF₆]³⁻?
    a) Both are high spin
    b) Both are low spin
    c) [Fe(CN)₆]³⁻ is low spin and [FeF₆]³⁻ is high spin
    d) [Fe(CN)₆]³⁻ is high spin and [FeF₆]³⁻ is low spin


16. The splitting of d-orbitals in an octahedral field gives:
    a) t_2g (higher) and e_g (lower)
    b) e_g (higher) and t_2g (lower)
    c) Both equal
    d) Depends on ligand


17. Which complex shows ionization isomerism?
    a) [Co(NH₃)₅Br]SO₄
    b) [Co(NH₃)₅SO₄]Br
    c) Both a and b
    d) None


18. The geometry of [Ni(CN)₄]²⁻ is:
    a) Tetrahedral
    b) Square planar
    c) Octahedral
    d) Trigonal planar


19. The stability of complexes depends on:
    a) Nature of ligand
    b) Charge on central ion
    c) Chelate effect
    d) All of these


20. The oxidation state of the central metal atom in [PtCl₂(NH₃)₂] is:
    a) 0
    b) +2
    c) +4
    d) −2

Answers & Solutions:

1-d) Six ligands → coordination number = 6.
2-c) Co + 2(en) + 2Cl = +1 → Co = +3.
3-d) Ambidentate ligands can link through two different atoms.
4-c) NO₂⁻ can link via N or O → ambidentate.
5-b) Cis and trans forms possible.
6-b) [Co(en)₃]³⁺ has chiral forms (optical isomerism).
7-c) Ethylenediamine (en) forms chelate rings.
8-a) CN⁻ is strong field → low spin → diamagnetic → 0 BM.
9-b) NO₂⁻ shows linkage isomerism (–ONO / –NO₂).
10-c) Ni(CO)₄ → sp³ hybridized, tetrahedral.
11-b) Color arises due to d–d transitions.
12-b) Valence Bond Theory explains geometry via hybridization and pairing.
13-a) Tetraaquadichlorochromium(III) chloride (oxidation state +3).
14-a) CN⁻ → strong field → dsp² → square planar.
15-c) CN⁻ strong field → low spin; F⁻ weak field → high spin.
16-b) e_g higher, t_2g lower in octahedral field.
17-c) Both a and b are ionization isomers.
18-b) [Ni(CN)₄]²⁻ → dsp² → square planar.
19-d) All factors affect stability.
20-b) Pt oxidation state = +2.