NEET ChemistryUpdated 19 Oct 2026

Coordination Compounds: NEET PYQs and weightage

Coordination Compounds carries 6.5 of 100 Chemistry marks in NEET by past-paper share: 46 of the 707 tagged NEET Chemistry PYQs in the ViJEEta bank (NEET 2013–2026). It ranks 2 of 26 Chemistry chapters.

Take the 25-question Coordination Compounds test Key facts ↓All NEET Chemistry chapters

6.5/100 Weight in Chemistry

Exam importance (4/5, by past-paper share)

46 NEET PYQs

517 Practice questions

493 With measured difficulty

How the weight is computed: this chapter's tagged NEET PYQs divided by all tagged NEET Chemistry PYQs in the bank (46 of 707), times 100, with repeated questions counted once. The bank does not store the year of each NEET question, so none is printed. Computed from the bank at build time. Updated 19 Oct 2026.

Coordination Compounds: key facts for NEET

16 facts the paper keeps asking, each with how it is asked. Copy it onto one page of your notebook: that page is this chapter's handbook.

Werner's theory
Primary valency = ionisable (oxidation state), secondary valency = non-ionisable (coordination number), and secondary valencies have fixed directions in space.
Asked as: $CoC l_{3} \cdot 6N H_{3}$ , $\cdot 5N H_{3}$ and $\cdot 4N H_{3}$ give 3, 2 and 1 mol $AgCl$ with excess $AgN O_{3}$ . Write their formulas.
Double salts vs complexes
Double salts (Mohr's salt $FeS O_{4} \cdot (N H_{4})_{2} S O_{4} \cdot 6 H_{2} O$ ) dissociate fully in water, but $K_{4} [Fe (CN)_{6}]$ gives no $F e^{2 +}$ test.
Asked as: Which of these gives the test for all its constituent ions in solution?
Denticity and chelates
en and oxalate ( $C_{2} O_{4}^{2 -}$ ) are didentate, $EDT A^{4 -}$ is hexadentate, and a di/polydentate ligand binding one metal forms a chelate.
Asked as: What is the denticity of EDTA, or which ligand forms a chelate?
Ambidentate ligands
Ambidentate ligands have two donor atoms but bind through only one: $N O_{2}^{-}$ (N) / $ON O^{-}$ (O), $SC N^{-}$ (S) / $NC S^{-}$ (N).
Asked as: Which of these is an ambidentate ligand?
Coordination number
Coordination number counts donor atoms, not ligands: $[Co (en)_{3}]^{3 +}$ and $[Fe (C_{2} O_{4})_{3}]^{3 -}$ both have CN $= 6$ .
Asked as: Find the CN and oxidation state of the metal in $[Co (en)_{2} C l_{2}]^{+}$ (CN $6$ , $+ 3$ ).
Homoleptic and heteroleptic complexes
Homoleptic complexes have one kind of ligand ( $[Co (N H_{3})_{6}]^{3 +}$ ); heteroleptic complexes have more than one ( $[Co (N H_{3})_{4} C l_{2}]^{+}$ ).
Asked as: Identify the heteroleptic complex in a list.
IUPAC nomenclature
Ligands go in alphabetical order before the metal. Anionic ligands end in -o (chlorido, cyanido); aqua, ammine, carbonyl and nitrosyl are the special neutral names. In an anionic complex the metal ends in -ate (ferrate, cuprate, argentate, aurate).
Asked as: Give the IUPAC name of $K_{3} [Fe (CN)_{6}]$ (potassium hexacyanidoferrate(III)).
Geometrical isomerism: square planar and tetrahedral
Square planar $[M X_{2} L_{2}]$ shows cis-trans isomerism, and $[MABXL]$ has 3 geometrical isomers. Tetrahedral complexes show no geometrical isomerism.
Asked as: How many geometrical isomers does $[Pt (N H_{3}) (Br) (Cl) (py)]$ have?
Geometrical isomerism: octahedral
Octahedral $[M X_{2} L_{4}]$ shows cis-trans isomerism, and $[M a_{3} b_{3}]$ shows fac-mer, e.g. $[Co (N H_{3})_{3} (N O_{2})_{3}]$ .
Asked as: fac and mer isomers are possible for which complex?
Optical isomerism
$[Co (en)_{3}]^{3 +}$ exists as d and l forms. cis- $[PtC l_{2} (en)_{2}]^{2 +}$ is optically active, trans is not.
Asked as: Which isomer of $[CoC l_{2} (en)_{2}]^{+}$ is optically active?
Linkage and coordination isomerism
Linkage isomerism: $[Co (N H_{3})_{5} (ONO)] C l_{2}$ is red (O-bonded) and $[Co (N H_{3})_{5} (N O_{2})] C l_{2}$ is yellow (N-bonded). Coordination isomerism: $[Co (N H_{3})_{6}] [Cr (CN)_{6}]$ / $[Cr (N H_{3})_{6}] [Co (CN)_{6}]$ .
Asked as: Name the type of isomerism shown by a given pair.
Ionisation and hydrate isomerism
Ionisation isomers: $[Co (N H_{3})_{5} (S O_{4})] Br$ and $[Co (N H_{3})_{5} Br] S O_{4}$ . Hydrate (solvate) isomers: $[Cr (H_{2} O)_{6}] C l_{3}$ (violet) and $[Cr (H_{2} O)_{5} Cl] C l_{2} \cdot H_{2} O$ (grey-green).
Asked as: Which isomer of the pair gives a white precipitate with $BaC l_{2}$ ?
VBT: cobalt complexes
$[Co (N H_{3})_{6}]^{3 +}$ is $d^{2} s p^{3}$ (inner orbital, low spin, diamagnetic), while $[Co F_{6}]^{3 -}$ is $s p^{3} d^{2}$ (outer orbital, high spin, 4 unpaired electrons).
Asked as: Give the hybridisation and magnetic nature of $[Co F_{6}]^{3 -}$ .
VBT: nickel complexes
$[NiC l_{4}]^{2 -}$ is $s p^{3}$ , tetrahedral and paramagnetic (2 unpaired). $[Ni (CN)_{4}]^{2 -}$ is $d s p^{2}$ , square planar and diamagnetic. $[Ni (CO)_{4}]$ is $s p^{3}$ , tetrahedral and diamagnetic.
Asked as: Match each Ni complex with its geometry and magnetic behaviour.
Crystal field theory (CFT)
$Δ_{t} = \frac{4}{9} Δ_{o}$
In an octahedral field $d$ splits into $t_{2 g}$ (lower) and $e_{g}$ (higher), and $Δ_{t} = \frac{4}{9} Δ_{o}$ . If $Δ_{o} < P$ you get high spin ( $d^{4} = t_{2 g}^{3} e_{g}^{1}$ ); if $Δ_{o} > P$ you get low spin ( $d^{4} = t_{2 g}^{4} e_{g}^{0}$ ).
Asked as: Write the configuration of a $d^{4}$ ion when $Δ_{o} > P$ .
Spectrochemical series and colour
Spectrochemical series: $I^{-} < B r^{-} < SC N^{-} < C l^{-} < S^{2 -} < F^{-} < O H^{-} < C_{2} O_{4}^{2 -} < H_{2} O < NC S^{-} < edt a^{4 -} < N H_{3} < en < C N^{-} < CO$ . Colour comes from d-d transitions: $[Ti (H_{2} O)_{6}]^{3 +}$ absorbs blue-green light (498 nm) and looks violet, and anhydrous $CuS O_{4}$ is white while hydrated $CuS O_{4}$ is blue.
Asked as: Arrange given ligands by field strength, or explain why anhydrous $CuS O_{4}$ is colourless.

Trap

Only ions outside the square bracket ionise. Cl⁻ inside the coordination sphere does NOT precipitate as AgCl, so count AgCl moles from the counter ions only.

How does NEET ask Coordination Compounds?

8 real previous-year questions from this chapter, as printed in the paper, each with its worked solution. Answer the first one here with no sign-in.

Q1ChemistryNEET UG PYQVBT Theory in Coordination Compounds

Try right here · No sign-in

Which of the following are paramagnetic? A. [NiCl

_{4}

]2– B. Ni(CO)

_{4}

C. [Ni(CN)

_{4}

]2– D. [Ni(H

_{2}

_{6}

]

^{2}

^{+}

E. Ni(PPh

_{3}

)

_{4}

Choose the correct answer from the options given below:

Answer key (A) & worked solution

Correct answer: Option A

A. [NiCl

_{4}

]2– = Ni

^{2 +}

is 3d

^{8}

paramagnetic D. [Ni(H

_{2}

_{6}

]

^{2 +}

= Ni

^{2 +}

is 3d

^{8}

paramagnetic

Q2ChemistryNEET UG PYQImportance of Coordination Compounds

Match List-I with List-II. List-IList-IIA. Haber process I. Fe catalyst B. Wacker oxidation II. PdCl

_{2}

C. Wilkinson catalyst III. [(PPh

_{3}

)

_{3}

RhCl] D. Ziegler catalyst IV. TiCl

_{4}

with Al(CH

_{3}

)

_{3}

Choose the correct answer from the options given below:

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

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

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

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

Answer key (A) & worked solution

Correct answer: Option A

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

Q3ChemistryNEET UG PYQCrystal Field Theory

Which of the following is the correct order of increasing field strength of ligands to form coordination compounds ?

F^{-} < S C N^{-} < C_{2} O_{4}^{2 -} < C N^{-}

C N^{-} < C_{2} O_{4}^{2 -} < S C N^{-} < F^{-}

S C N^{-} < F^{-} < C_{2} O_{4}^{2 -} < C N^{-}

S C N^{-} < F^{-} < C N^{-} < C_{2} O_{4}^{2 -}

Answer key (C) & worked solution

Correct answer: Option C

The spectrochemical series is a list of ligands based on the strength of their interaction with metal ions. It is often listed, from weaker to stronger ligands, something like this: I− < Br− < S2− < SCN− < Cl− < NO

_{3}

− < N

_{3}

− < F− < OH− < C

_{2}

_{4}

2− < H

_{2}

O < NCS− < CH

_{3}

CN < py < NH

_{3}

Q4ChemistryNEET UG PYQOrganometallic Compounds

An example of a sigma bonded organometallic compound is

AFerrocene

BCobaltocene

CRuthenocene

DGrignard’s reagent

Answer key (D) & worked solution

Correct answer: Option D

Grignard's reagent i.e., RMgX is σ − bonded organometallic compound.

Q5ChemistryNEET UG PYQStability of Coordination Compounds in Solution

Which complex compound is most stable?

[Co (N H_{3})_{3} (N O_{3})_{3}]

[CoC l_{2} (en)_{2}] N O_{3}

[Co (N H_{3})_{6}]_{2} (S O_{4})_{3}

[Co (N H_{3})_{4} (H_{2} O) Br] (N O_{3})_{2}

Answer key (B) & worked solution

Correct answer: Option B

due to Chelation effect of (en).

Q6ChemistryNEET UG PYQVBT Theory in Coordination Compounds

Match List I with List II :

List I (Complex/ion)

List II (Shape/geometry)

A.

[Pt (Cl_{2}) (NH_{3})_{2}]

(I)

Octahedral

B.

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

(II)

Trigonal bipyramidal

C.

[NiCl_{4}]^{2 -}

(III)

Square planar

D.

[Fe (CO)_{5}]

(IV)

Tetrahedral

Choose the correct answer from the options given below :

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

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

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

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

Answer key (D) & worked solution

Correct answer: Option D

- In

[Pt (Cl_{2}) (NH_{3})_{2}]

; Pt has

d s p^{2}

hybridisation, so shape of complex is square planar. - In

[Co (NH_{3})_{6}] Cl_{3}

; Co has

d^{2} s p^{3}

hybridisation so shape of complex is octahedral. - In

[NiCl_{4}]^{2 -}

; Ni has

s p^{3}

hybridisation so shape of complex ion is tetrahedral. - In

[Fe (CO)_{5}]

; shape of complex is trigonal bipyramidal.

Q7ChemistryNEET UG PYQWerner's Theory

The correct order of the stoichiometries of AgCl formed when AgNO

_{3}

in excess is treated with the complexes CoCl

_{3}

6NH

_{3}

, CoCl

_{3}

. 5NH

_{3}

, CoCl

_{3}

. 4NH

_{3}

respectively is

A3AgCl, 2AgCl, 1AgCl

B2AgCl, 3AgCl, 1AgCl

C1AgCl, 3AgCl, 2AgCl

D3AgCl, 1AgCl, 2AgCl

Answer key (A) & worked solution

Correct answer: Option A

Complexes are respectively

[C O (N H_{3})_{6}] C l_{3}, [C o (N H_{3})_{5} C l] C l_{2}

and

[C o (N H_{3})_{4} C l_{2}] C l

Q8ChemistryNEET UG PYQComponents of Coordination Compounds

AIF

_{3}

is soluble in HF only in presence of KF. It is due to the formation of

_{3}

[AIF

_{6}

]

BAlH

_{3}

CK([AlF

_{3}

_{3}

[AlF

_{3}

_{3}

]

Answer key (A) & worked solution

Correct answer: Option A

A l F_{3} + 3 K F \to K_{3} [A l F_{6}]

Which topics in Coordination Compounds carry the most questions?

The 12 busiest of 13 topics, by tagged PYQs, then practice questions. Counted from the bank. Updated 19 Oct 2026.

Topic	PYQs	Practice questions
VBT Theory in Coordination Compounds	12	101
Crystal Field Theory	10	69
Isomerism in Coordination Compounds	5	91
Introduction to Coordination Compounds	5	28
Nomenclature of Coordination Compounds	3	58
Importance of Coordination Compounds	3	9
Organometallic Compounds	2	30
Components of Coordination Compounds	2	24
Werner's Theory	2	15
Ligands	1	65
Stability of Coordination Compounds in Solution	1	12
Sidgwick's EAN Rule	0	13

Why does Coordination Compounds show "–" until you answer 3 questions?

Unknown is not zero. Until you answer at least 3 graded questions in Coordination Compounds, ViJEEta shows – instead of a zero or a 50% default. Book exercises can raise chapter mastery up to 0.60, adaptive practice up to 0.75, and only a timed chapter test or mock can certify 0.80 and above.

How ViJEEta scores you

What happens when you test Coordination Compounds?

Every chapter test is 25 questions. It starts at moderate difficulty and adapts after each saved answer. If you open a solution before answering, that attempt earns no credit, so your mastery stays honest.

Start the Coordination Compounds test

Chapters either side of Coordination Compounds by weight

Chemical Bonding and Molecular Structure Weight 9.2/100 Hydrocarbons Weight 5.9/100 Solutions Weight 5.7/100

Coordination Compounds: NEET PYQs and weightage

Coordination Compounds: key facts for NEET

Werner's theory

Double salts vs complexes

Denticity and chelates

Ambidentate ligands

Coordination number

Homoleptic and heteroleptic complexes

IUPAC nomenclature

Geometrical isomerism: square planar and tetrahedral

Geometrical isomerism: octahedral

Optical isomerism

Linkage and coordination isomerism

Ionisation and hydrate isomerism

VBT: cobalt complexes

VBT: nickel complexes

Crystal field theory (CFT)

Spectrochemical series and colour

How does NEET ask Coordination Compounds?

Which topics in Coordination Compounds carry the most questions?

Why does Coordination Compounds show "–" until you answer 3 questions?

What happens when you test Coordination Compounds?

Chapters either side of Coordination Compounds by weight