Inorganic Chemistry

IIT-JAM Chemistry — Coordination Chemistry previous year questions

34 questions · 2001–2005 · all with verified answer · last checked 2026-11-06

Q1 · 2005-2022 · 2 marks

Among the following complexes, (i) \left[\mathrm{Ru}(\text { bipyridyl })_{3}\right]^{+} (ii) [\mathrm{Cr}(\mathrm{EDTA})]^{-} (iii) trans- \left[\mathrm{CrCl}_{2} \text { (oxalate) }{ }_{2}\right]^{3-} (iv) cis- \left[\mathrm{CrCl}_{2} \text { (oxalate) }{ }_{2}\right]^{3-} the ones that show chirality are

(a) (i), (ii), (iv)
(b) (i), (ii), (iii)
(c) (ii), (iii), (iv)
(d) (i), (iii), (iv)

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Answer: (a)

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Q2 · 2005-2022 · 2 marks

The crystal field stabilization energy of high spin \mathrm{d}^{7} octahedral complex is

(a) \frac{-4}{5}\Delta_{0}+2\mathrm{P}
(b) \frac{-4}{5}\Delta_{0}+3\mathrm{P}
(c) \frac{-9}{5}\Delta_{0}+2\mathrm{P}
(d) \frac{-9}{5}\Delta_{0}+3\mathrm{P}

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Answer: (a)

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Q3 · 2005-2022 · 2 marks

The complex with the most intense colour among the following is

(a) \left[\mathrm{FeF}_{6}\right]^{3-}
(b) \left[\mathrm{MnCl}_{4}\right]^{2-}
(c) \left[\mathrm{CoCl}_{4}\right]^{2-}
(d) \left[\mathrm{CoF}_{6}\right]^{3-}

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Answer: (c)

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Q4 · 2005-2022 · 2 marks

The octahedral crystal field splitting \left(\Delta_{0}\right) of d orbital energies of the following metal ions decreases in the order

(a) \mathrm{Co}^{2+}>\mathrm{Co}^{3+}>\mathrm{Rh}^{3+}
(b) \mathrm{Rh}^{3+}>\mathrm{Co}^{3+}>\mathrm{Co}^{2+}
(c) \mathrm{Rh}^{3+}>\mathrm{Co}^{2+}>\mathrm{Co}^{3+}
(d) \mathrm{Co}^{3+}>\mathrm{Co}^{2+}>\mathrm{Rh}^{3+}

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Answer: (b)

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Q5 · 2005-2022 · 2 marks

The optical absorption spectrum of \left[\mathrm{Ti}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{3+} has its absorption maximum at 20300 \mathrm{~cm}^{-1}. The magnitude of crystal field stabilization energy in \mathrm{cm}^{-1} is

(a) 8120
(b) 16240
(c) 24360
(d) 50750

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Answer: (a)

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Q6 · 2005-2022 · 2 marks

The ligand with only sigma (\sigma) bonding character is

(a) \mathrm{CN}^{-}
(b) \mathrm{CH}_{3}{ }^{-}
(c) CO
(d) NO

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Answer: (b)

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Q7 · 2005-2022 · 2 marks

For tetrahedral complexes, which always exhibit high spin states, the maximum CFSE (crystal field stabilization energy) is:

(a) -8 Dq
(b) -12 Dq
(c) -16 Dq
(d) -20 Dq

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Answer: (b)

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Q8 · 2005-2022 · 2 marks

Addition of an aqueous solution of Fe(II) to potassium hexacyanochromate (III) produces a brick-red coloured complex, which turn dark green at 100^{\circ} \mathrm{C}. The dark green complexes is

(a) \mathrm{Fe}_{4}\left[\mathrm{Cr}(\mathrm{CN})_{6}\right]_{3}
(b) \mathrm{KFe}\left[\mathrm{Cr}(\mathrm{CN})_{6}\right]
(c) \mathrm{KCr}\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]
(d) \mathrm{Fe}\left[\mathrm{Cr}(\mathrm{CN})_{6}\right]

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Answer: (c)

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Q9 · 2005-2022 · 2 marks

The oxide that has the inverse spinel structure is

(a) \mathrm{FeCr}_{2}\mathrm{O}_{4}
(b) \mathrm{MnCr}_{2}\mathrm{O}_{4}
(c) \mathrm{CoAl}_{2}\mathrm{O}_{4}
(d) \mathrm{CoFe}_{2}\mathrm{O}_{4}

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Answer: (d)

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Q10 · 2005-2022 · 2 marks

The tetrachloro complexes of Ni(II) and Pd(II) respectively, are (atomic numbers of Ni and Pd are 28 and 46 respectively)

(a) diamagnetic and diamagnetic
(b) paramagnetic and paramagnetic
(c) diamagnetic and paramagnetic
(d) paramagnetic and diamagnetic

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Answer: (d)

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Q11 · 2005-2022 · 2 marks

A filter paper moistened with cadmium acetate solution turns yellow upon exposure to \mathrm{H}_{2} \mathrm{~S}. The transition responsible for the yellow colour is

(a) d-d
(b) metal to ligand charge transfer
(c) ligand to metal charge transfer
(d) \sigma-\sigma^{*}

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Answer: (c)

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Q12 · 2005-2022 · 2 marks

The first row transition metal complexes having tetrahedral geometry are high-spin due to

(a) \Delta_{\mathrm{t}}>\mathrm{P}
(b) \Delta_{\mathrm{t}}<\mathrm{P}
(c) \Delta_{\mathrm{t}}=\mathrm{P}
(d) \Delta_{\mathrm{t}}>\Delta_{0}

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Answer: (b)

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Q13 · 2005-2022 · 2 marks

The normal spinel among the following mixed metal-oxides is

(a) \mathrm{CoFe}_{2} \mathrm{O}_{4}
(b) \mathrm{NiFe}_{2} \mathrm{O}_{4}
(c) \mathrm{CuFe}_{2} \mathrm{O}_{4}
(d) \mathrm{ZnFe}_{2} \mathrm{O}_{4}

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Answer: (d)

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Q14 · 2005-2022 · 2 marks

The ground state term for a free ion with 3 \mathrm{~d}^{7} configuration is

(a) { }^{4} \mathrm{~F}_{3 / 2}
(b) { }^{4} \mathrm{~F}_{9 / 2}
(c) { }^{4} \mathrm{~F}_{1 / 2}
(d) { }^{4} \mathrm{~F}_{5 / 2}

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Answer: (b)

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Q15 · 2005-2022 · 2 marks

Given that the expected spin-only magnetic moment for \left(\mathrm{Et}_{4} \mathrm{~N}\right)_{2}\left[\mathrm{NiCl}_{4}\right] is 2.83 \mu_{\mathrm{B}}, the total number of unpaired electrons in this complex is ____ .

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Answer: 2

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Q16 · 2005-2022 · 2 marks

The complex that is expected to show orbital contribution to the overall magnetic moment is

(a) \left[\mathrm{Cr}(\mathrm{CN})_{6}\right]^{3-}
(b) \left[\mathrm{Co}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{2+}
(c) \left[\mathrm{Ni}(\mathrm{en})_{3}\right]^{2+}
(d) \left[\mathrm{Cu}\left(\mathrm{NH}_{3}\right)_{6}\right]^{2+} (IIT JAM 2016)

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Answer: (b)

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Q17 · 2005-2022 · 2 marks

The total number of isomers possible for the molecule \left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{4} \mathrm{Cl}\left(\mathrm{NO}_{2}\right)\right]^{+}is ____ .

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Answer: 4

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Q18 · 2005-2022 · 2 marks

The complexes \left[\mathrm{Pt}(\mathrm{CN})_{4}\right]^{2-} and \left[\mathrm{NiCl}_{4}\right]^{2-}, respectively are

(a) paramagnetic, paramagnetic
(b) diamagnetic, diamagnetic
(c) paramagnetic, diamagnetic
(d) diamagnetic, paramagnetic

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Answer: (d)

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Q19 · 2005-2022 · 2 marks

The crystal field stabilization energy (CFSE) in \left[\mathrm{Mn}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{2+} is

(a) 0 \Delta_{0}
(b) 2.0 \Delta_{0}-2 \mathrm{P}
(c) 0.4 \Delta_{0}-2 \mathrm{P}
(d) 2.0 \Delta_{0}

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Answer: (a)

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Q20 · 2005-2022 · 2 marks

The True Statement about \left[\mathrm{Cu}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{2+} is

(a) All Cu-O bond lengths are equal
(b) One Cu-O bond length is shorter than the remaining five
(c) Three \mathrm{Cu}-\mathrm{O} bond lengths are shorter than the remaining three
(d) Four \mathrm{Cu}-\mathrm{O} bond lengths are shorter than the remaining two

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Answer: (d)

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Q21 · 2005-2022 · 2 marks

I he red colour of ruby is due to

(a) d-d transition of \mathrm{Cr}^{3+} ion in \mathrm{Cr}_{2} \mathrm{O}_{3} lattice
(b) d-d transition of \mathrm{Cr}^{3+} ion in \mathrm{Al}_{2} \mathrm{O}_{3} lattice
(c) ligand to metal charge transfer transition
(d) metal to metal charge transfer transition (IIT JAM 2017)

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Answer: (b)

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Q22 · 2005-2022 · 2 marks

The number of unpaired electron(s) in \mathrm{K}_{2} \mathrm{NiF}_{6} is ____ .

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Answer: 0

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Q23 · 2005-2022 · 2 marks

The correct order of enthalpy of hydration for the transition metal ions is

(a) \mathrm{Cr}^{2+}>\mathrm{Mn}^{2+}>\mathrm{Co}^{2+}>\mathrm{Ni}^{2+}
(b) \mathrm{Ni}^{2+}>\mathrm{Co}^{2+}>\mathrm{Mn}^{2+}>\mathrm{Cr}^{2+}
(c) \mathrm{Ni}^{2+}>\mathrm{Co}^{2+}>\mathrm{Cr}^{2+}>\mathrm{Mn}^{2+}
(d) \mathrm{Cr}^{2+}>\mathrm{Mn}^{2+}>\mathrm{Ni}^{2+}>\mathrm{Co}^{2+}

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Answer: (c)

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Q24 · 2005-2022 · 2 marks

The correct order of wavelength of absorption \left(\lambda_{\max }\right) of the Cr -complexes is (en = ethylenediamine)

(a) \left[\mathrm{CrF}_{6}\right]^{3-}>\left[\mathrm{Cr}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{3+}>\left[\mathrm{Cr}(\mathrm{en})_{3}\right]^{3+}>\left[\mathrm{Cr}(\mathrm{CN})_{6}\right]^{3-}
(b) \left[\mathrm{Cr}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{3+}>\left[\mathrm{CrF}_{6}\right]^{3-}>\left[\mathrm{Cr}(\mathrm{en})_{3}\right]^{3+}>\left[\mathrm{Cr}(\mathrm{CN})_{6}\right]^{3-}
(c) \left[\mathrm{Cr}(\mathrm{CN})_{6}\right]^{3-}>\left[\mathrm{Cr}(\mathrm{en})_{3}\right]^{3+}>\left[\mathrm{Cr}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{3+}>\left[\mathrm{CrF}_{6}\right]^{3-}
(d) \left[\mathrm{Cr}(\mathrm{en})_{3}\right]^{3+}>\left[\mathrm{Cr}(\mathrm{CN})_{6}\right]^{3-}>\left[\mathrm{Cr}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{3+}>\left[\mathrm{CrF}_{6}\right]^{3-}

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Answer: (a)

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Q25 · 2005-2022 · 2 marks

The number of possible isomers for \left[\mathrm{Pt}(\mathrm{py})\left(\mathrm{NH}_{3}\right) \mathrm{BrCl}\right] is ____ (py is pyridine)

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Answer: 3

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Q26 · 2005-2022 · 2 marks

The correct order of \Delta_{0} (the octahedral crystal field splitting of d orbitals) values for the following anionic metal complexes is

(a) \left[\operatorname{Ir}(\mathrm{CN})_{6}\right]^{3-}<\left[\operatorname{Rh}(\mathrm{CN})_{6}\right]^{3-}<\left[\mathrm{RhI}_{6}\right]^{3-}<\left[\mathrm{CoI}_{6}\right]^{3-}
(b) \left[\mathrm{CoI}_{6}\right]^{3-}<\left[\mathrm{RhI}_{6}\right]^{3-}<\left[\mathrm{Rh}(\mathrm{CN})_{6}\right]^{3-}<\left[\operatorname{Ir}(\mathrm{CN})_{6}\right]^{3-}
(c) \left[\mathrm{CoI}_{6}\right]^{3-}<\left[\mathrm{Rh}(\mathrm{CN})_{6}\right]^{3-}<\left[\mathrm{RhI}_{6}\right]^{3-}<\left[\operatorname{Ir}(\mathrm{CN})_{6}\right]^{3-}
(d) \left[\operatorname{Ir}(\mathrm{CN})_{6}\right]^{3-}<\left[\mathrm{CoI}_{6}\right]^{3-}<\left[\mathrm{Rh}(\mathrm{CN})_{6}\right]^{3-}<\left[\mathrm{RhI}_{6}\right]^{3-}

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Answer: (b)

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Q27 · 2005-2022 · 2 marks

The observed magnetic moments of octahedral \mathrm{Mn}^{3+}, \mathrm{Fe}^{3+} and \mathrm{Co}^{3+} complexes are 4.95,6.06 and 0.00 BM , respectively. The correct option for the electronic configuration of \mathrm{Mn}^{3+}, \mathrm{Fe}^{3+} and \mathrm{Co}^{3+} metal ions in these complexes, respectively, is

(a) \mathrm{t}_{2 \mathrm{~g}}^{4} \mathrm{e}_{\mathrm{g}}^{0}, \mathrm{t}_{2 \mathrm{~g}}^{2} \mathrm{e}_{\mathrm{g}}^{2} and \mathrm{t}_{2 \mathrm{~g}}^{4} \mathrm{e}_{\mathrm{g}}^{2} III < II < I
(b) \mathrm{t}_{2 \mathrm{~g}}^{3} \mathrm{e}_{\mathrm{g}}^{1}, \mathrm{t}_{2 \mathrm{~g}}^{5} \mathrm{e}_{\mathrm{g}}^{0} and \mathrm{t}_{2 \mathrm{~g}}^{6} \mathrm{e}_{\mathrm{g}}^{0} I < II < III
(c) \mathrm{t}_{2 \mathrm{~g}}^{3} \mathrm{e}_{\mathrm{g}}^{1}, \mathrm{t}_{2 \mathrm{~g}}^{3} \mathrm{e}_{\mathrm{g}}^{2} and \mathrm{t}_{2 \mathrm{~g}}^{6} \mathrm{e}_{\mathrm{g}}^{0} II < III < I
(d) \mathrm{t}_{2 \mathrm{~g}}^{3} \mathrm{e}_{\mathrm{g}}^{1}, \mathrm{t}_{2 \mathrm{~g}}^{3} \mathrm{e}_{\mathrm{g}}^{2} and \mathrm{t}_{2 \mathrm{~g}}^{4} \mathrm{e}_{\mathrm{g}}^{2} \left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{5} \mathrm{Br}\right]^{2+} (II) and \left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{5} \text { Il }\right]^{2+} (III), is I < III < II

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Answer: (c)

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Q28 · 2005-2022 · 2 marks

The total number of all possible isomers of \left[\mathrm{Co}\left(\mathrm{H}_{2} \mathrm{NCH}_{2} \mathrm{CH}_{2} \mathrm{NH}_{2}\right)_{2} \mathrm{Cl}_{2}\right]^{+}and \left[\mathrm{Co}\left(\mathrm{H}_{2} \mathrm{NCH}_{2} \mathrm{CH}_{2} \mathrm{NH}_{2}\right)_{3}\right]^{3+}

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Answer: 5

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Q29 · 2001-2022 · 2 marks

The d - orbitals involved in the hybridization to form square planar and trigonal bipyramidal geometries are, respectively.

(a) \mathrm{d}_{\mathrm{z}^{2}} and \mathrm{d}_{\mathrm{z}^{2}}
(b) \mathrm{d}_{\mathrm{yz}} and \mathrm{d}_{\mathrm{z}^{2}}
(c) \mathrm{d}_{\mathrm{x}^{2}-\mathrm{y}^{2}} and \mathrm{d}_{\mathrm{z}^{2}}
(d) \mathrm{d}_{\mathrm{x}^{2}-\mathrm{y}^{2}} and \mathrm{d}_{\mathrm{yz}} IIT JAM 2021

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Answer: (c)

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Q30 · 2005-2022 · 2 marks

Reaction of \left[\mathrm{Ni}(\mathrm{CN})_{4}\right]^{2-} with metallic potassium in liquid ammonia at -33^{\circ} \mathrm{C} yields complex E . The geometry and magnetic behavior of E, respectively, are

(a) Octahedral and paramagnetic
(b) Tetrahedral and diamagnetic
(c) Square pyramidal and paramagnetic
(d) Square planar and diamagnetic

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Answer: (b)

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Q31 · 2005-2022 · 2 marks

According to the crystal field theory, \mathrm{d}-\mathrm{d} transition observed in \left[\mathrm{Ti}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{3+} is

(a) Laporte forbidden and spin allowed
(b) Laporte allowed and spin forbidden
(c) Laporte forbidden and spin forbidden
(d) Laporte allowed and spin allowed

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Answer: (a)

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Q32 · 2005-2022 · 2 marks

The total number of microstates possible for a \mathrm{d^8} electronic configuration is ____.

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Answer: 45

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Q33 · 2005-2022 · 2 marks

The number of unpaired electrons in \left[\mathrm{Co}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{2+} is ____ .

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Answer: 3

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Q34 · 2005-2022 · 2 marks

Total degeneracy (number of microstates) for a \mathrm{Ti}^{3+} ion in spherical symmetry is ____ . ANSWERS KEY

1.	(a)	2.	(a)	3.	(*)	4.	(c)	5.	(b,c)	6.	(b)	7.	(a)
8.	(3)	9.	(*)	10.	(b)	11.	(-249.5)	12.	(a)	13.	(b)
14.	(d)	15.	(*)	16.	(a)	17.	(b)	18.	(c)	19.	(c)	20.	(d)
21.	(*)	22.	(*)	23.	(*)	24.	(d)	25.	(*)	26.	(*)
27.	(*)	28.	(a)	29.	(0)	30.	(c)	31.	(c)	32.	(b)	33.	(110.75)
34.	(d)	35.	(b)	36.	(2)	37.	(b)	38.	(4)	39.	(d)	40.	(a)
41.	(d)	42	(b,c)	43.	(b)	44.	(b)	45.	(0)	46.	(c)	47.	(a)
48.	(b,c)	49.	(3)	50.	(b)	51.	(1nm)	52.	(c)	53.	(b)	54.	(a)
55.	(5)	56.	(c)	57.	(c,d)	58.	(b)	59.	(b)	60.	(-84.58)
61.	(a,d)	62.	(a)	63.	(45)	64.	(a)	65.	(6)	66.	(3)	67.	(3)
68.	(10)
Magnitude of JTD \quad \Rightarrow \mathrm{e}_{\mathrm{g}} (unsymmetry) >\mathrm{t}_{2 \mathrm{~g}} (unsymmetry)
(B) (I) \left[\mathrm{CoF}_{6}\right]^{3-} \rightarrow \mathrm{d}^{6}
(II) \left[\mathrm{Fe}(\mathrm{CN})_{6}\right]^{3-} \rightarrow \mathrm{d}^{5} Low spin
(III) \left[\mathrm{NiCl}_{4}\right]^{2-} \mathrm{d}^{8}
tetrahedral \begin{array}{l} \text { CFSE } \Rightarrow[(-0.6 \times 4)+(4 \times 0.4)] \Delta_{\mathrm{t}}=-0.8 \Delta_{\mathrm{t}} \text { M.M. }=\sqrt{2(2+2)}=\sqrt{8} \mathrm{BM} \end{array}

Check Hints solution (*) 3(A) \left[\mathrm{Cu}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{2+}-more distorted tetrahedral Structure for this question

\begin{array}{l} \text { CFSE } \Rightarrow[(-0.6 \times 4)+(4 \times 0.4)] \Delta_{\mathrm{t}}=-0.8 \Delta_{\mathrm{t}} \text { M.M. }=\sqrt{2(2+2)}=\sqrt{8} \mathrm{BM} \end{array}

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Answer: 10

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