${\rm{CuS}}{{\rm{O}}_4}$ decolourises on addition of KCN, the product is:

${\left[ {{\rm{Cu}}{{\left( {{\rm{CN}}} \right)}_4}} \right]^{3 - }}$

${\rm{Cu}}\left( {{\rm{CN}}} \right)_4^{2 - }$

${\rm{Cu}}{\left( {{\rm{CN}}} \right)_2}$

The IUPAC name of ${{\rm{K}}_2}\left[ {{\rm{Ni}}{{\left( {{\rm{CN}}} \right)}_4}} \right]$ is

Potassium tetracyanatonickelate (III)

Potassium tetracyanatonickel (II)

Potassium tetracyanonickel (III)

An aqueous solution of ${\rm{CoC}}{{\rm{l}}_2}$ on addition of excess of concentrated ${\rm{HCl}}$ turns blue to formation of

${\left[ {{\rm{CoC}}{{\rm{l}}_4}} \right]^{2 - }}$

${\left[ {{\rm{Co}}{{\left( {{{\rm{H}}_2}{\rm{O}}} \right)}_2}{\rm{C}}{{\rm{l}}_4}} \right]^{2 - }}$

${\left[ {{\rm{Co}}{{\left( {{{\rm{H}}_2}{\rm{O}}} \right)}_2}2{\rm{C}}{{\rm{l}}_4}} \right]^{2 - }}$

$\left[ {{\rm{Co}}{{\left( {{{\rm{H}}_2}{\rm{O}}} \right)}_4}{\rm{C}}{{\rm{l}}_2}} \right]$

The IUPAC name of the compound $\left[ {{\rm{Cu}}{{\left( {{\rm{N}}{{\rm{H}}_3}} \right)}_4}{{\left( {{\rm{N}}{{\rm{O}}_3}} \right)}_2}} \right]$ is:

Tetraamminecopper(II) dinitrite

Tetraamminecopper(III) dinitrite

Which of the following organometallic compound is $\sigma \,\,{\rm{and}}\,\,\pi $ bonded?

$\left[ {{\rm{Fe}}{{\left( {{{\rm{\eta }}^5} - {{\rm{C}}_5}{{\rm{H}}_5}} \right)}_2}} \right]$

${\rm{Fe}}{\left( {{\rm{C}}{{\rm{H}}_3}} \right)_3}$

${\left[ {{\rm{Co}}{{\left( {{\rm{CO}}} \right)}_5}{\rm{N}}{{\rm{H}}_3}} \right]^{2 + }}$

${\rm{K}}\left[ {{\rm{PtC}}{{\rm{l}}_3}\left( {{{\rm{\eta }}^2} - {{\rm{C}}_2}{{\rm{H}}_4}} \right)} \right]$

The IUPAC name of $\left[ {{\rm{Ni}}{{\left( {{\rm{N}}{{\rm{H}}_3}} \right)}_4}} \right]\left[ {{\rm{NiC}}{{\rm{l}}_4}} \right]{\rm{\;}}$ is

Tetrachloro nickel (II) – tetraammine nickel (II)

Tetraammine nickel (II) –tetrachloro nickel(II)

Tetrachloro nickel (II) –tetraammine nickelate(0)

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NEET • CHEMISTRY • CO-ORDINATION COMPOUNDS

Co-ordination compounds practice · Mixed difficulty

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1 Medium

1 of 320

Understanding +4 | -1

The complexes

\left[ {\mathrm{PtC}{\mathrm{l}_2}{{\left( {\mathrm{N}{\mathrm{H}_3}} \right)}_4}} \right]\mathrm{B}{\mathrm{r}_2}\mathrm{\;and\;}\left[ {\mathrm{PtB}{\mathrm{r}_2}{{\left( {\mathrm{N}{\mathrm{H}_3}} \right)}_4}} \right]\mathrm{C}{\mathrm{l}_2}\mathrm{\;}

are example for isomerism

View answer and explanation

Correct option: C

Ionization

Option C (Ionization) is correct because the complexes differ in the ions present outside the coordination sphere.

2 Hard

2 of 320

Analyzing +4 | -1

The total number of stereoisomers for the complex

\left[\mathrm{Cr}(\mathrm{Ox})_{2} \mathrm{ClBr}\right]^{3-}

(where

\text{ox =}

oxalate) is

View answer and explanation

Correct option: A

Option A (3) is correct because the complex can exhibit cis and trans isomers, and the cis isomer is chiral, leading to a total of 3 stereoisomers.

3 Medium

3 of 320

Application +4 | -1

The value of

x

on the

{\left[ {\mathrm{Ni}{{\left( {\mathrm{CN}} \right)}_4}} \right]^x}

is:

View answer and explanation

Correct option: B

-2

The correct answer is -2 because the overall charge of the complex ion

{\left[ {\mathrm{Ni}{{\left( {\mathrm{CN}} \right)}_4}} \right]^x}

is -2.

4 Medium

4 of 320

Application +4 | -1

Excited state configuration of

\mathrm{M}{\mathrm{n}^{2 + }}

View answer and explanation

Correct option: B

t_{2g}^3e_g^2

Option B is correct. The excited state configuration of

\mathrm{M}{\mathrm{n}^{2 + }}

t_{2g}^3e_g^2

because one or more electrons from the

t_{2g}

orbitals get excited to the

e_g

orbitals.

5 Medium

5 of 320

Analyzing +4 | -1

\mathrm{CuS}{\mathrm{O}_4}

decolourises on addition of KCN, the product is:

View answer and explanation

Correct option: B

{\left[ {\mathrm{Cu}{{\left( {\mathrm{CN}} \right)}_4}} \right]^{3 - }}

Option B (

{\left[ {\mathrm{Cu}{{\left( {\mathrm{CN}} \right)}_4}} \right]^{3 - }}

) is correct because Cu2+ is reduced to Cu+ by cyanide ions, and then forms a stable complex with excess cyanide.

6 Easy

6 of 320

Application +4 | -1

The IUPAC name of

{\mathrm{K}_2}\left[ {\mathrm{Ni}{{\left( {\mathrm{CN}} \right)}_4}} \right]

View answer and explanation

Correct option: A

Potassium tetracyanonickelate (II)

Option A (Potassium tetracyanonickelate (II)) is correct because it correctly names the compound, indicating the potassium cation, the tetracyano ligands, the nickelate anion, and the oxidation state of nickel.

7 Medium

7 of 320

Analyzing +4 | -1

Which of the following statements is not correct?

View answer and explanation

Correct option: A

In oxyhaemoglobin

\mathrm{F}{\mathrm{e}^{2 + }}

is paramagnetic

Option A (In oxyhaemoglobin

\mathrm{F}{\mathrm{e}^{2 + }}

is paramagnetic) is correct because in oxyhemoglobin, Fe2+ is actually diamagnetic due to strong field ligand nature of oxygen.

8 Medium

8 of 320

Analyzing +4 | -1

Which one of the following is an inner orbital complex as well as diamagnetic in nature?

View answer and explanation

Correct option: B

{\left[ {\mathrm{Co}{{\left( {\mathrm{N}{\mathrm{H}_3}} \right)}_6}} \right]^{3 + }}

Option B (

{\left[ {\mathrm{Co}{{\left( {\mathrm{N}{\mathrm{H}_3}} \right)}_6}} \right]^{3 + }}

) is correct because Co3+ forms a low-spin, inner orbital complex with NH3, making it diamagnetic.

9 Hard

9 of 320

Application +4 | -1

A solution made by dissolving

0.875 \mathrm{~g}

of compound

\mathrm{Co}\left(\mathrm{NH}_3\right)_4 \mathrm{Cl}_3

25 \mathrm{~g}

of water freezes at

-0.56^{\circ} \mathrm{C}

.

The structural formula of the complex, if cryoscopic constant of water is

1.86 \mathrm{~K} \mathrm{~kg} \mathrm{~mol}^{-1}

, is

View answer and explanation

Correct option: C

\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_4 \mathrm{Cl}_2\right] \mathrm{Cl}

Option C (

\left[\mathrm{Co}(\mathrm{NH}_3)_4 \mathrm{Cl}_2\right] \mathrm{Cl}

) is correct because the calculated Van't Hoff factor matches the dissociation of the complex into two ions.

10 Hard

10 of 320

Understanding +4 | -1

Assertion : Square planar complex

{\text{M}}{{\text{a}}_{\text{2}}}{{\text{b}}_{\text{2}}}

has two optical isomers.

Reason : Mirror image of

{\text{M}}{{\text{a}}_{\text{2}}}{{\text{b}}_{\text{2}}}

is non-super imposable.

View answer and explanation

Correct option: D

If both Assertion & Reason are false

Option D is correct because square planar complexes of the type

{\text{M}}{{\text{a}}_{\text{2}}}{{\text{b}}_{\text{2}}}

do not have optical isomers, and their mirror images are superimposable.

11 Easy

11 of 320

Application +4 | -1

The pair of compounds having metals in their highest oxidation state is

View answer and explanation

Correct option: B

{\left[ {\mathrm{Mn}{\mathrm{O}_4}} \right]^ - },\mathrm{Cr}{\mathrm{O}_2}\mathrm{C}{\mathrm{l}_2}

Option B (

{\left[ {\mathrm{Mn}{\mathrm{O}_4}} \right]^ - },\mathrm{Cr}{\mathrm{O}_2}\mathrm{C}{\mathrm{l}_2}

) is correct because Mn in

{\left[ {\mathrm{Mn}{\mathrm{O}_4}} \right]^ - }

and Cr in

\mathrm{Cr}{\mathrm{O}_2}\mathrm{C}{\mathrm{l}_2}

are in their highest oxidation states, +7 and +6 respectively.

12 Hard

12 of 320

Understanding +4 | -1

Which of the following compounds is not coloured yellow?

View answer and explanation

Correct option: A

Z{n_2}[Fe{(CN)_6}]

Option A (

Z{n_2}[Fe{(CN)_6}]

) is correct because it is white or bluish-white, while the other options are yellow.

13 Easy

13 of 320

Remembering +4 | -1

In haemoglobin the iron shows oxidation state:

View answer and explanation

Correct option: A

Option D (Ions or molecules linked by coordinate bonds to a central metal atom or ion) is correct because ligands can be either ions or molecules that donate electron pairs to the central metal atom/ion.

14 Easy

14 of 320

Remembering +4 | -1

An imperfect complex of a complex compound is 100% ionized; the compound is called:

View answer and explanation

Correct option: A

Double salt

Option A (Double salt) is correct because double salts dissociate into their constituent ions when dissolved in water, exhibiting 100% ionization.

15 Hard

15 of 320

Understanding +4 | -1

Assertion : In the complex

{{\text{K}}_{\text{2}}}\left[ {{\text{PtC}}{{\text{l}}_{\text{6}}}} \right]

, coordination number of Pt is 6.

Reason : In the complex six coordinate bonds are formed between Pt and chloro ligands.

View answer and explanation

Correct option: A

If both Assertion & Reason are True & the Reason is a correct explanation of the Assertion.

Option A is correct because the coordination number of Pt is indeed 6, and this is due to the formation of six coordinate bonds with the chloro ligands.

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16 Medium

16 of 320

Analyzing +4 | -1

Both geometrical and optical isomerisms are shown by

View answer and explanation

Correct option: A

{\left[ {CO{{\left( {en} \right)}_2}C{l_2}} \right]^ + }

Option A (

{\left[ {CO{{\left( {en} \right)}_2}C{l_2}} \right]^ + }

) is correct because it can exhibit both geometrical (cis and trans) and optical isomerism (for the cis isomer).

17 Hard

17 of 320

Understanding +4 | -1

Assertion : All tetrahedral complexes are mainly high spin and the low spin configurations are rarely observed.
Reason:

\Delta {\text{t}}

is always much smaller even with stronger field ligands and it is never energetically favourable to pair up the electrons.

View answer and explanation

Correct option: A

If both Assertion & Reason are True & the Reason is a correct explanation of the Assertion.

Option A is correct because tetrahedral complexes usually have high spin configurations due to the smaller crystal field splitting energy (

\Delta t

), and this is because it's rarely energetically favorable to pair up electrons.

18 Hard

18 of 320

Understanding +4 | -1

An aqueous solution of

\mathrm{CoC}{\mathrm{l}_2}

on addition of excess of concentrated

\mathrm{HCl}

turns blue to formation of

View answer and explanation

Correct option: A

{\left[ {\mathrm{CoC}{\mathrm{l}_4}} \right]^{2 - }}

Option A (

{\left[ {\mathrm{CoC}{\mathrm{l}_4}} \right]^{2 - }}

) is correct because the addition of excess concentrated HCl to an aqueous solution of

\mathrm{CoC}{\mathrm{l}_2}

leads to the formation of the tetrahedral complex

{\left[ {\mathrm{CoC}{\mathrm{l}_4}} \right]^{2 - }}

which is blue in color.

19 Hard

19 of 320

Understanding +4 | -1

Homoleptic octahedral complexes of a metal ion '

{M^{3 + }}

' with three monodentate ligands

{L_1},{L_2}

and

{L_3}

absorb wavelengths in the region of green, blue and red respectively. The increasing order of the ligand strength is

View answer and explanation

Correct option: C

{L_3} < {L_1} < {L_2}

Option C (

{L_3} < {L_1} < {L_2}

) is correct because the energy absorbed is inversely proportional to the wavelength, and the ligand strength is directly proportional to the energy absorbed. Red < Green < Blue implies

{L_3} < {L_1} < {L_2}

20 Medium

20 of 320

Application +4 | -1

Which complex is diamagnetic?

View answer and explanation

Correct option: A

{\left[ {\mathrm{Fe}{{\left( {\mathrm{CN}} \right)}_6}} \right]^{4 - }}

Option A ([Fe(CN)6]^4-) is correct because Fe in this complex has a d⁶ configuration, and CN- is a strong field ligand, causing pairing of all electrons, resulting in a diamagnetic complex.

21 Hard

21 of 320

Analyzing +4 | -1

Select the correct statement(s).

View answer and explanation

Correct option: B

The octahedral complex formed by joining the

\mathrm{CN}^{-}

ligands to

\mathrm{Fe}^{+3}

ion has theoretical value of spin magnetic moment equal to 1.73 B.M.

Option B is correct because the octahedral complex of

\mathrm{Fe}^{+3}

with

\mathrm{CN}^{-}

has one unpaired electron, resulting in a spin magnetic moment of approximately 1.73 B.M.

22 Easy

22 of 320

Understanding +4 | -1

The two compounds pentaamminesulphatocobalt (III) bromide and pentaamminesulphatocobalt(III) chloride represent:

View answer and explanation

Correct option: D

No isomerism

Option D is correct. The two compounds are not isomers because they differ only in the counter-ion (bromide vs. chloride), not in the arrangement of ligands around the central metal ion.

23 Easy

23 of 320

Application +4 | -1

The IUPAC name of the compound

\left[ {\mathrm{Cu}{{\left( {\mathrm{N}{\mathrm{H}_3}} \right)}_4}{{\left( {\mathrm{N}{\mathrm{O}_3}} \right)}_2}} \right]

is:

View answer and explanation

Correct option: B

Dinitratotetraamminecopper(II)

The correct answer is B (Dinitratotetraamminecopper(II)). The IUPAC name follows the rules for naming coordination compounds: ligands are named alphabetically, followed by the metal with its oxidation state in Roman numerals.

24 Easy

24 of 320

Understanding +4 | -1

Which of the following organometallic compound is

\sigma \,\,\mathrm{and}\,\,\pi

bonded?

View answer and explanation

Correct option: C

\left[ {\mathrm{Fe}{{\left( {{\mathrm{\eta }^5} - {\mathrm{C}_5}{\mathrm{H}_5}} \right)}_2}} \right]

Option C (

\left[ {\mathrm{Fe}{{\left( {{\mathrm{\eta }^5} - {\mathrm{C}_5}{\mathrm{H}_5}} \right)}_2}} \right]

) is correct because Ferrocene has both sigma and pi bonding between Fe and the cyclopentadienyl rings.

25 Hard

25 of 320

Understanding +4 | -1

The theory that can completely/ properly explain the nature of bonding in

[Ni{(CO)_4}]

View answer and explanation

Correct option: D

Molecular orbital theory

Option D (Molecular orbital theory) is correct because it provides the most complete description of bonding in coordination complexes, including back-bonding effects, which are crucial for understanding the stability of carbonyl complexes like

[Ni{(CO)_4}]

26 Easy

26 of 320

Remembering +4 | -1

According to effective atomic number rule the central metal acquires:

View answer and explanation

Correct option: A

Inert gas configuration

Option C (Two

\mathrm{N}

atoms and four

\mathrm{O}

atoms) is correct because EDTA has two nitrogen and four oxygen atoms that can donate electron pairs to the metal ion.

27 Easy

27 of 320

Application +4 | -1

The IUPAC name of

\left[ {\mathrm{Ni}{{\left( {\mathrm{N}{\mathrm{H}_3}} \right)}_4}} \right]\left[ {\mathrm{NiC}{\mathrm{l}_4}} \right]\mathrm{\;}

View answer and explanation

Correct option: C

Tetraammine nickel (II) –tetrachloro nickelate(II)

Option C (Tetraammine nickel (II) –tetrachloro nickelate(II)) is correct because it follows the IUPAC naming conventions for coordination compounds, correctly identifying the cation and anion.

28 Medium

28 of 320

Remembering +4 | -1

The crystal field splitting energy for octahedral 

\left(\Delta_0\right)

and tetrahedral

\left(\Delta_t\right)

complexes is related to

View answer and explanation

Correct option: C

{\Delta _t} = \frac{4}{9}{\Delta _0}

Option C is correct because the relationship between crystal field splitting energy for octahedral (Δo) and tetrahedral (Δt) complexes is given by Δt = (4/9)Δo.

29 Easy

29 of 320

Understanding +4 | -1

Complexes with

C{N^ - }

ligands are usually:

View answer and explanation

Correct option: B

Low spin complexes

The correct answer is B (Low spin complexes) because

C{N^-}

is a strong field ligand, which causes pairing of electrons and results in low spin complexes.

30 Hard

30 of 320

Remembering +4 | -1

What is the overall formation equilibrium constant for the ion

{\left[ {M{L_4}} \right]^{2 - }}

ion, given that

{\mathrm{\beta }_4}

for this complex is

2.5 \times {10^{13}}?

View answer and explanation

Correct option: A

2.5 \times {10^{13}}

Option A (

2.5 \times {10^{13}}

) is correct because the overall formation equilibrium constant,

\beta_4

, is directly given as

2.5 \times 10^{13}

Revision notes and key takeaways

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