Coordination Compounds

2023 Q201 JEE Mains MCQ
14 Mar 2026

Chiral complex from the following is :

Here en = ethylene diamine

A.
$\mathrm{cis-[PtCl_2(en)_2]^{2+}}$
B.
$\mathrm{trans-[Co(NH_3)_4Cl_2]^{+}}$
C.
$\mathrm{trans-[PtCl_2(en)_2]^{2+}}$
D.
$\mathrm{cis-[PtCl_2(NH_3)_2]}$
2023 Q202 JEE Mains MCQ
14 Mar 2026

Match List I with List II

List I
Coordination entity
List II
Wavelength of light absorbed in nm
A. $\mathrm{[CoCl(NH_3)_5]^{2+}}$ I. 310
B. $\mathrm{[Co(NH_3)_6]^{3+}}$ II. 475
C. $\mathrm{[Co(CN)_6]^{3-}}$ III. 535
D. $\mathrm{[Cu(H_2O)_4]^{2+}}$ IV. 600

Choose the correct answer from the options given below :

A.
A-IV, B-I, C-III, D-II
B.
A-III, B-II, C-I, D-IV
C.
A-III, B-I, C-II, D-IV
D.
A-II, B-III, C-IV, D-I
2023 Q203 JEE Mains MCQ
14 Mar 2026

The hybridization and magnetic behaviour of cobalt ion in $\mathrm{[Co(NH_3)_6]^{3+}}$ complex, respectively is :

A.
$\mathrm{sp^3d^2}$ and paramagnetic
B.
$\mathrm{sp^3d^2}$ and diamagnetic
C.
$\mathrm{d^2sp^3}$ and diamagnetic
D.
$\mathrm{d^2sp^3}$ and paramagnetic
2023 Q204 JEE Mains MCQ
14 Mar 2026

Which of the following cannot be explained by crystal field theory?

A.
The order of spectrochemical series
B.
Stability of metal complexes
C.
Magnetic properties of transition metal complexes
D.
Colour of metal complexes
2023 Q205 JEE Mains MCQ
14 Mar 2026

The primary and secondary valencies of cobalt respectively in $\mathrm{[Co(NH_3)_5Cl]Cl_2}$ are :

A.
2 and 8
B.
2 and 6
C.
3 and 5
D.
3 and 6
2023 Q206 JEE Mains Numerical
14 Mar 2026
The homoleptic and octahedral complex of $\mathrm{Co}^{2+}$ and $\mathrm{H}_{2} \mathrm{O}$ has ___________ unpaired electron(s) in the $t_{2\mathrm{g}}$ set of orbitals.
2023 Q207 JEE Mains Numerical
14 Mar 2026

The ratio of spin-only magnetic moment values $\mu_{\text {eff }}\left[\mathrm{Cr}(\mathrm{CN})_{6}\right]^{3-} / \mu_{\text {eff }}\left[\mathrm{Cr}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{3+}$ is _________.

2023 Q208 JEE Mains Numerical
14 Mar 2026

For a metal ion, the calculated magnetic moment is $4.90 ~\mathrm{BM}$. This metal ion has ___________ number of unpaired electrons.

2023 Q209 JEE Mains Numerical
14 Mar 2026

In potassium ferrocyanide, there are ________ pairs of electrons in the $t_{2g}$ set of orbitals.

2023 Q210 JEE Mains Numerical
14 Mar 2026

The observed magnetic moment of the complex $\left.\left[\operatorname{Mn}(\underline{N} C S)_{6}\right)\right]^{x^{-}}$ is $6.06 ~\mathrm{BM}$. The numerical value of $x$ is __________.

2023 Q211 JEE Mains Numerical
14 Mar 2026

Number of ambidentate ligands in a representative metal complex $\left[\mathrm{M}(\mathrm{en})(\mathrm{SCN})_{4}\right]$ is ___________.

[en = ethylenediamine]

2023 Q212 JEE Mains Numerical
14 Mar 2026

The spin only magnetic moment of $\left[\mathrm{Mn}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{2+}$ complexes is _________ B.M. (Nearest integer)

(Given : Atomic no. of Mn is 25)

2023 Q213 JEE Mains Numerical
14 Mar 2026
If the CFSE of $\left[\mathrm{Ti}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{3+}$ is $-96.0 \mathrm{~kJ} / \mathrm{mol}$, this complex will absorb maximum at wavelength ___________ $\mathrm{nm}$. (nearest integer)

Assume Planck's constant (h) $=6.4 \times 10^{-34} \mathrm{Js}$, Speed of light $(\mathrm{c})=3.0 \times 10^{8} \mathrm{~m} / \mathrm{s}$ and Avogadro's

Constant $\left(\mathrm{N}_{\mathrm{A}}\right)=6 \times 10^{23} / \mathrm{mol}$
2023 Q214 JEE Mains Numerical
14 Mar 2026

The sum of bridging carbonyls in $\mathrm{W(CO)_6}$ and $\mathrm{Mn_2(CO)_{10}}$ is ____________.

2023 Q215 JEE Mains Numerical
14 Mar 2026

Total number of moles of AgCl precipitated on addition of excess of AgNO$_3$ to one mole each of the following complexes $\mathrm{[Co(NH_3)_4Cl_2]Cl,[Ni(H_2O)_6]Cl_2,[Pt(NH_3)_2Cl_2]}$ and $\mathrm{[Pd(NH_3)_4]Cl_2}$ is ___________.

2023 Q216 JEE Mains Numerical
14 Mar 2026

The number of paramagnetic species from the following is _____________.

$\mathrm{{[Ni{(CN)_4}]^{2 - }},[Ni{(CO)_4}],{[NiC{l_4}]^{2 - }}}$

$\mathrm{{[Fe{(CN)_6}]^{4 - }},{[Cu{(N{H_3})_4}]^{2 + }}}$

$\mathrm{{[Fe{(CN)_6}]^{3 - }}\,and\,{[Fe{({H_2}O)_6}]^{2 + }}}$

2023 Q217 JEE Mains Numerical
14 Mar 2026

The d-electronic configuration of $\mathrm{[CoCl_4]^{2-}}$ in tetrahedral crystal field in ${e^mt_2^n}$. Sum of "m" and "number of unpaired electrons" is ___________

2023 Q218 JEE Advanced MCQ
14 Mar 2026
Match the electronic configurations in List-I with appropriate metal complex ions in List-II and choose the correct option.

[Atomic Number: $\mathrm{Fe}=26, \mathrm{Mn}=25, \mathrm{Co}=27$ ]

List - I List - II
(P) $t_{2 g}^6 e_g^0$ (1) $\left[\mathrm{Fe}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{2+}$
(Q) $t_{2 g}^3 e_g^2$ (2) $\left[\mathrm{Mn}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{2+}$
(R) $\mathrm{e}^2 \mathrm{t}_2^3$ (3) $\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_6\right]^{3+}$
(S) $t_{2 g}^4 e_g^2$ (4) $\left[\mathrm{FeCl}_4\right]^{-}$
(5) $\left[\mathrm{CoCl}_4\right]^{2-}$
A.
$\mathrm{P} \rightarrow 1 ; \mathrm{Q} \rightarrow 4 ; \mathrm{R} \rightarrow 2 ; \mathrm{S} \rightarrow 3$
B.
$P \rightarrow 1 ; \mathrm{Q} \rightarrow 2 ; \mathrm{R} \rightarrow 4 ; \mathrm{S} \rightarrow 5$
C.
$\mathrm{P} \rightarrow 3 ; \mathrm{Q} \rightarrow 2 ; \mathrm{R} \rightarrow 5 ; \mathrm{S} \rightarrow 1$
D.
$\mathrm{P} \rightarrow 3 ; \mathrm{Q} \rightarrow 2 ; \mathrm{R} \rightarrow 4 ; \mathrm{S} \rightarrow 1$
2023 Q219 JEE Advanced MSQ
14 Mar 2026
The complex(es), which can exhibit the type of isomerism shown by $\left[\operatorname{Pt}\left(\mathrm{NH}_3\right)_2 \mathrm{Br}_2\right]$, is(are) :

[en $=\mathrm{H}_2 \mathrm{NCH}_2 \mathrm{CH}_2 \mathrm{NH}_2$ ]
A.
$\left[\mathrm{Pt}(\mathrm{en})(\mathrm{SCN})_2\right]$
B.
$\left[\mathrm{Zn}\left(\mathrm{NH}_3\right)_2 \mathrm{Cl}_2\right]$
C.
$\left[\mathrm{Pt}\left(\mathrm{NH}_3\right)_2 \mathrm{Cl}_4\right]$
D.
$\left[\mathrm{Cr}(\mathrm{en})_2\left(\mathrm{H}_2 \mathrm{O}\right)\left(\mathrm{SO}_4\right)\right]^{+}$
2023 Q220 TS-EAMCET MCQ
20 May 2026

The sum of oxidation state and co-ordination number of central metal atom is maximum with respect to which of the following complex?

A.

$\mathrm{K}_3\left[\mathrm{Cr}\left(\mathrm{C}_2 \mathrm{O}_4\right)_3\right]$

B.

$\left[\mathrm{Cr}(\mathrm{CO})_6\right]$

C.

$\mathrm{K}_2\left[\mathrm{PtCl}_6\right]$

D.

$\mathrm{K}_4\left[\mathrm{Fe}(\mathrm{CN})_6\right]$

2023 Q221 TS-EAMCET MCQ
20 May 2026

$ \text { Match the following. } $

$ \begin{array}{llll} \hline & \begin{array}{l} \text { List-I } \\ (\text { Complex }) \end{array} & & \begin{array}{l} \text { List-II } \\ \text { (Spin only magnetic } \\ \text { moment) } \end{array} \\ \hline \text { A. } & {\left[\mathrm{CoF}_6\right]^{3-}} & \text { I. } & 0 \\ \hline \text { B. } & {\left[\mathrm{Co}\left(\mathrm{C}_2 \mathrm{O}_4\right)_3\right]^{3-}} & \text { II. } & \sqrt{24} \\ \hline \text { C. } & {\left[\mathrm{FeF}_6\right]^{3-}} & \text { III. } & \sqrt{8} \\ \hline \text { D. } & {\left[\mathrm{Mn}(\mathrm{CN})_6\right]^{3-}} & \text { IV. } & \sqrt{35} \\ \hline & & \text { V. } & \sqrt{15} \\ \hline \end{array} $

The correct answer is

A.

A-V, B-II, C-IV, D-I

B.

A-II, B-I, C-IV, D-III

C.

A-II, B-I, C-V, D-III

D.

A-III, B-II, C-I, D-V

2023 Q222 TS-EAMCET MCQ
20 May 2026

Identify the correct set for $\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_6\right]^{3+}$ ion.

(Hybridisation of $\mathrm{Co}^{3+}$, type of complex, number of unpaired electrons in the complex ion respectively.)

A.

$d^2 s p^3$, inner orbital complex, zero

B.

$s p^3 d^2$, outer orbital complex, three

C.

$d^2 s p^3$, inner orbital complex, two

D.

$s p^3 d^2$, outer orbital complex, zero

2023 Q223 TS-EAMCET MCQ
20 May 2026
  • According to Werner's theory, the number of groups bonded to the central metal atom/ion in a coordination complex represent.

A.

oxidation state

B.

primary valency

C.

secondary valency

D.

polyhedron

2023 Q224 TS-EAMCET MCQ
20 May 2026

Identify the incorrect match from the following.

A.
$\left[\mathrm{Cr}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right] \mathrm{Br}_2$ - Paramagnetic
B.
$\mathrm{Na}_4\left[\mathrm{Fe}(\mathrm{CN})_6\right]$ - Diamagnetic
C.
$\left[\mathrm{Ni}(\mathrm{CO})_4\right]$ - Paramagnetic
D.
$\mathrm{Na}_2\left[\mathrm{NiCl}_4\right]$ - Paramagnetic
2023 Q225 TS-EAMCET MCQ
20 May 2026
Match the following.TS EAMCET 2023 (Online) 12th May Morning Shift Chemistry - Coordination Compounds Question 24 EnglishThe correct answer is Table
A.
A-II, B-III, C-IV, D-I
B.
A-III, B-IV, C-II, D-I
C.
A-IV, B-III, C-I, D-II
D.
A-II, B-I, C-IV, D-III
2023 Q226 BITSAT MCQ
11 Jun 2026

The complex showing a spin-only magnetic moment of $2.82 \mathrm{~BM}$ is

A.
$\left[\mathrm{Ni}(\mathrm{Cl})_4\right]^{3-}$
B.
$\left[\mathrm{NiCl}_4\right]^{2-}$
C.
$\mathrm{Ni}\left(\mathrm{PPh}_3\right)_4$
D.
$\left[\mathrm{Ni}(\mathrm{CN})_4\right]^{2-}$
2023 Q227 BITSAT MCQ
11 Jun 2026

The correct statement with respect to the complexes $\mathrm{Ni}(\mathrm{CO})_4$ and $[\mathrm{Ni}(\mathrm{CN})_4]^{2-}$ is

A.
nickel is in the same oxidation state in both.
B.
Both have square planar geometry.
C.
have square planar and tetrahedral geometry, respectively.
D.
have tetrahedral and square planar geometry, respectively.
2022 Q228 JEE Mains MCQ
14 Mar 2026

Octahedral complexes of copper(II) undergo structural distortion (Jahn-Teller). Which one of the given copper (II) complexes will show the maximum structural distortion? (en - ethylenediamine; $\mathrm{H}_{2} \mathrm{~N}_{-} \mathrm{CH}_{2}-\mathrm{CH}_{2}-\mathrm{NH}_{2}$)

A.
$\left[\mathrm{Cu}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right] \mathrm{SO}_{4}$
B.
$\left[\mathrm{Cu}(\mathrm{en})\left(\mathrm{H}_{2} \mathrm{O}\right)_{4}\right] \mathrm{SO}_{4}$
C.
cis-$\left[\mathrm{Cu}\left(\mathrm{en})_{2} \mathrm{Cl}_{2}\right]\right.$
D.
trans-$\left[\mathrm{Cu}\left(\mathrm{en})_{2} \mathrm{Cl}_{2}\right]\right.$
2022 Q229 JEE Mains MCQ
14 Mar 2026

Match List I with List II

List - I (Complex) List - II (Hybridization)
(A) $Ni{(CO)_4}$ (I) $s{p^3}$
(B) ${[Ni{(CN)_4}]^{2 - }}$ (II) $s{p^3}{d^2}$
(C) ${[Co{(CN)_6}]^{3 - }}$ (III) ${d^2}s{p^3}$
(D) ${[Co{F_6}]^{3 - }}$ (IV) $ds{p^2}$

Choose the correct answer from the options given below :

A.
A-IV, B-I, C-III, D-II
B.
A-I, B-IV, C-III, D-II
C.
A-I, B-IV, C-II, D-III
D.
A-IV, B-I, C-II, D-III
2022 Q230 JEE Mains MCQ
14 Mar 2026

Low oxidation state of metals in their complexes are common when ligands :

A.
have good $\pi$-accepting character
B.
have good $\sigma$-donor character
C.
are having good $\pi$-donating ability
D.
are having poor $\sigma$-donating ability
2022 Q231 JEE Mains MCQ
14 Mar 2026

$\mathrm{Fe}^{3+}$ cation gives a prussian blue precipitate on addition of potassium ferrocyanide solution due to the formation of :

A.
$\left[\mathrm{Fe}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]_{2}\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]$
B.
$\mathrm{Fe}_{2}\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]_{2}$
C.
$\mathrm{Fe}_{3}\left[\mathrm{Fe}(\mathrm{OH})_{2}(\mathrm{CN})_{4}\right]_{2}$
D.
$\mathrm{Fe}_{4}\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]_{3}$
2022 Q232 JEE Mains MCQ
14 Mar 2026

The metal complex that is diamagnetic is (Atomic number: $\mathrm{Fe}, 26 ; \mathrm{Cu}, 29)$

A.
$\mathrm{K}_{3}\left[\mathrm{Cu}(\mathrm{CN})_{4}\right]$
B.
$\mathrm{K}_{2}\left[\mathrm{Cu}(\mathrm{CN})_{4}\right]$
C.
$\mathrm{K}_{3}\left[\mathrm{Fe}(\mathrm{CN})_{4}\right]$
D.
$\mathrm{K}_{4}\left[\mathrm{FeCl}_{6}\right]$
2022 Q233 JEE Mains MCQ
14 Mar 2026

The correct order of energy of absorption for the following metal complexes is :

A : [Ni(en)3]2+ , B : [Ni(NH3)6]2+ , C : [Ni(H2O)6]2+

A.
C < B < A
B.
B < C < A
C.
C < A < B
D.
A < C < B
2022 Q234 JEE Mains MCQ
14 Mar 2026

Correct formula of the compound which gives a white precipitate with BaCl2 solution, but not with AgNO3 solution, is :

A.
[Co(NH3)5Br]SO4
B.
[Co(NH3)5SO4]Br
C.
[Pt(NH3)4Cl2]Br2
D.
[Pt(NH3)4Br2]Cl2
2022 Q235 JEE Mains MCQ
14 Mar 2026

Given below are two statements.

$\bullet$ Statement I : In CuSO4 . 5H2O, Cu-O bonds are present.

$\bullet$ Statement II : In CuSO4 . 5H2O, ligands coordinating with Cu(II) ion are O-and S-based ligands.

In the light of the above statements, choose the correct answer from the options given below.

A.
Both Statement I and Statement II are correct.
B.
Both Statement I and Statement II are incorrect.
C.
Statement I is correct but Statement II is incorrect.
D.
Statement I is incorrect but Statement II is correct.
2022 Q236 JEE Mains MCQ
14 Mar 2026

Given below are two statements :

Statement I : [Ni(CN)4]2$-$ is square planar and diamagnetic complex, with dsp2 hybridization for Ni but [Ni(CO)4] is tetrahedral, paramagnetic and with sp3-hybridication for Ni.

Statement II : [NiCl4]2$-$ and [Ni(CO)4] both have same d-electron configuration have same geometry and are paramagnetic.

In light the above statements, choose the correct answer from the options given below :

A.
Both Statement I and Statement II are true.
B.
Both Statement I and Statement II are false.
C.
Statement I is correct but Statement II is false.
D.
Statement I is false but Statement II is correct.
2022 Q237 JEE Mains MCQ
14 Mar 2026

Arrange the following coordination compounds in the increasing order of magnetic moments. (Atomic numbers : Mn = 25; Fe = 26)

A. [FeF6]3$-$

B. [Fe(CN)6]3$-$

C. [MnCl6]3$-$ (high spin)

D. [Mn(CN)6]3$-$

Choose the correct answer from the options given below :

A.
A < B < D < C
B.
B < D < C < A
C.
A < C < D < B
D.
B < D < A < C
2022 Q238 JEE Mains MCQ
14 Mar 2026

Which of the following will have maximum stabilization due to crystal field?

A.
[Ti(H2O)6]3+
B.
[Co(H2O)6]2+
C.
[Co(CN)6]3$-$
D.
[Cu(NH3)4]2+
2022 Q239 JEE Mains MCQ
14 Mar 2026

Which statement is not true with respect to nitrate ion test?

A.
A dark brown ring is formed at the junction of two solutions.
B.
Ring is formed due to nitroferrous sulphate complex.
C.
The brown complex is [Fe(H2O)5 (NO)]SO4.
D.
Heating the nitrate salt with conc. H2SO4, light brown fumes are evolved.
2022 Q240 JEE Mains MCQ
14 Mar 2026

Transition metal complex with highest value of crystal field splitting ($\Delta$0) will be :

A.
[Cr(H2O)6]3+
B.
[Mo(H2O)6]3+
C.
[Fe(H2O)6]3+
D.
[Os(H2O)6]3+
2022 Q241 JEE Mains MCQ
14 Mar 2026

Match List - I with List - II :

List - I List -II
(A) ${[PtC{l_4}]^{2 - }}$ (I) $s{p^3}d$
(B) $Br{F_5}$ (II) ${d^2}s{p^3}$
(C) $PC{l_5}$ (III) $ds{p^2}$
(D) ${[Co{(N{H_3})_6}]^{3 + }}$ (IV) $s{p^3}{d^2}$

Choose the most appropriate answer from the options given below :

A.
(A)-(II), (B)-(IV), (C)-(I), (D)-(III)
B.
(A)-(III), (B)-(IV), (C)-(I), (D)-(II)
C.
(A)-(III), (B)-(I), (C)-(IV), (D)-(II)
D.
(A)-(II), (B)-(I), (C)-(IV), (D)-(III)
2022 Q242 JEE Mains Numerical
14 Mar 2026

Sum of oxidation state (magnitude) and coordination number of cobalt in $\mathrm{Na}\left[\mathrm{Co}(\mathrm{bpy}) \mathrm{Cl}_{4}\right]$ is _________.

JEE Main 2022 (Online) 29th July Evening Shift Chemistry - Coordination Compounds Question 175 English

2022 Q243 JEE Mains Numerical
14 Mar 2026

$\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]^{3-}$ should be an inner orbital complex. Ignoring the pairing energy, the value of crystal field stabilization energy for this complex is $(-)$ ____________ $\Delta_{0}$. (Nearest integer)

2022 Q244 JEE Mains Numerical
14 Mar 2026

Total number of relatively more stable isomer(s) possible for octahedral complex $\left[\mathrm{Cu}(\mathrm{en})_{2}(\mathrm{SCN})_{2}\right]$ will be _________.

2022 Q245 JEE Mains Numerical
14 Mar 2026

The conductivity of a solution of complex with formula $\mathrm{CoCl}_{3}\left(\mathrm{NH}_{3}\right)_{4}$ corresponds to 1 : 1 electrolyte, then the primary valency of central metal ion is __________.

2022 Q246 JEE Mains Numerical
14 Mar 2026

The difference between spin only magnetic moment values of $\left[\mathrm{Co}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]\mathrm{Cl}_{2}$ and $\left[\mathrm{Cr}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right] \mathrm{Cl}_{3}$ is ___________.

2022 Q247 JEE Mains Numerical
14 Mar 2026

Consider the following metal complexes :

$\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{6}\right]^{3+}$

$\left[\mathrm{CoCl}\left(\mathrm{NH}_{3}\right)_{5}\right]^{2+}$

$\left[\mathrm{Co}(\mathrm{CN})_{6}\right]^{3-}$

$\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{5}\left(\mathrm{H}_{2} \mathrm{O}\right)\right]^{3+}$

The spin-only magnetic moment value of the complex that absorbes light with shortest wavelength is _____________ B. M. (Nearest integer)

2022 Q248 JEE Mains Numerical
14 Mar 2026

In the following brown complex, the oxidation state of iron is +_____________.

${[Fe{({H_2}O)_6}]^{2 + }} + NO \to \mathop {{{[Fe{{({H_2}O)}_5}(NO)]}^{2 + }}}\limits_{\text{Brown complex}} + {H_2}O$

2022 Q249 JEE Mains Numerical
14 Mar 2026

Spin only magnetic moment ($\mu$s) of ${K_3}[Fe{(CN)_6}]$ is ____________ B.M.

(Nearest integer)

2022 Q250 JEE Mains Numerical
14 Mar 2026

${[Fe{(CN)_6}]^{4 - }}$

${[Fe{(CN)_6}]^{3 - }}$

${[Ti{(CN)_6}]^{3 - }}$

${[Ni{(CN)_4}]^{2 - }}$

${[Co{(CN)_6}]^{3 - }}$

Among the given complexes, number of paramagnetic complexes is ____________.