Coordination Compounds- NEET Previous Year Questions with Complete Solutions

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Why Coordination Compounds Is a Must-Master Chapter for NEET 

Coordination Compounds (Class 12, Chapter 9) is one of the most concept-dense chapters in Inorganic Chemistry — and one of the most rewarding when prepared systematically. It contributes 2–3 questions every year in NEET UG, worth approximately 8–12 marks, across a predictable and finite set of question types.

What makes this chapter particularly valuable is its specificity. Unlike some chapters where question types are broad and unpredictable, Coordination Compounds questions in NEET almost always come from these exact areas: IUPAC nomenclature, ligand classification, coordination number, geometrical and optical isomerism, Crystal Field Theory (CFT) splitting, and effective atomic number (EAN). Master these six areas and the chapter yields near-perfect marks.

The chapter also has direct relevance to the medical world — haemoglobin (an iron coordination complex) and chlorophyll (a magnesium coordination complex) are examples that NEET uses to anchor conceptual questions.

💡 Expert Tip by eSaral Chemistry Faculty: "Coordination Compounds is the chapter where students either score 3-for-3 or 0-for-3 — there is rarely a middle ground. Students who lose marks here almost always lose them on IUPAC naming (wrong charge on metal) or on CFT (confusing high-spin and low-spin). These are fixable errors. Practise naming 10 complexes and drawing 5 CFT splitting diagrams and this chapter becomes a reliable source of free marks."

 NEET Previous Year Questions — Coordination Compounds with Solutions

Chapter Overview: Topics and Subtopics 

What This Chapter Covers

NEET Weightage Analysis: Year-Wise Question Count

How Many Questions Come From Coordination Compounds in NEET?

Average: 2.5 questions per year — approximately 10 marks. The high repeatability of question types makes this one of the most efficiently learnable chapters in NEET Chemistry.

💡 Expert Tip by eSaral Chemistry Faculty: "CFT and IUPAC nomenclature together account for nearly half of all Coordination Compounds questions in NEET. For CFT — know the splitting diagram for both octahedral (d_z², d_x²-y² higher; t₂g lower) and tetrahedral complexes, and which ligands are strong-field vs weak-field. For IUPAC — practise until you can name any given complex and determine the oxidation state of the metal in under 60 seconds."

Key Concepts You Must Know Before Solving PYQs 

1. Types of Ligands — Complete Reference

2. IUPAC Nomenclature — Rules in Order

Step 1: Name the cation first, then the anion (just like ionic compounds).

Step 2: Within the complex ion, name ligands in alphabetical order before the metal.

Step 3: Ligand name prefixes:

• Anionic ligands: add suffix -o (Cl⁻ = chlorido, CN⁻ = cyanido, NO₂⁻ = nitrito)
• Neutral ligands: use special names — NH₃ = ammine, H₂O = aqua, CO = carbonyl, NO = nitrosyl
• Cationic ligands: add suffix -ium (rare)

Step 4: Number of ligands: di, tri, tetra, penta, hexa (or bis, tris, tetrakis if ligand name contains a number).

Step 5: Metal name:

• In cationic/neutral complex: use English name of metal + oxidation state in Roman numerals in parentheses
• In anionic complex: use Latin name + suffix -ate (Fe → ferrate, Cu → cuprate, Au → aurate, Pb → plumbate, Sn → stannate, Ag → argentate)

Step 6: Oxidation state of metal = charge of complex − sum of charges of all ligands.

Quick IUPAC Practice Examples

3. Crystal Field Theory (CFT) — Splitting Diagrams

Octahedral complex (most common in NEET):

• d orbitals split into two sets:
  • e_g (higher energy): d_z², d_x²-y² — 2 orbitals
  • t₂g (lower energy): d_xy, d_xz, d_yz — 3 orbitals
• Energy gap = Δ_o (octahedral splitting energy)

Tetrahedral complex:

• Split into t₂ (higher) and e (lower) — reverse of octahedral
• Δ_t = 4/9 × Δ_o (much smaller than octahedral — most tetrahedral complexes are high-spin)

Strong-field vs Weak-field Ligands (Spectrochemical Series)

Weak-field (small Δ) → High-spin → more unpaired electrons → paramagnetic

Strong-field (large Δ) → Low-spin → fewer unpaired electrons → less paramagnetic (may be diamagnetic)

Spectrochemical series (partial — weakest to strongest field): I⁻ < Br⁻ < SCN⁻ < Cl⁻ < F⁻ < OH⁻ < ox²⁻ < H₂O < NH₃ < en < CN⁻ < CO

4. Isomerism in Coordination Compounds

Structural Isomerism:

Stereoisomerism:

5. EAN Rule

EAN (Effective Atomic Number) = Atomic number of metal − Electrons lost (oxidation state) + Electrons gained from ligands (2 × number of ligands for monodentate)

EAN = Z − oxidation state + 2 × (coordination number)

A complex is stable when its EAN equals the atomic number of the nearest noble gas.

Example: [Fe(CO)₅] → Fe: Z = 26, oxidation state = 0, coordination number = 5 EAN = 26 − 0 + 2 × 5 = 36 = Kr ✓ (stable)

How to Study Coordination Compounds for Maximum NEET Marks {#how-to-study}

Step-by-Step Study Plan

Step 1 — Learn the basic terminology with examples (Day 1) Central metal ion, ligand, coordination sphere, counter ion, coordination number — write a definition and one example for each. For ligand types (mono/bi/poly/ambidentate), make a table with 2–3 examples per type. This is the vocabulary of the chapter — without it, no question is solvable.

Step 2 — Master IUPAC nomenclature with 10 practice complexes (Day 1–2) IUPAC naming is the single most tested skill in this chapter. Follow the five-step naming sequence:

1. Name the cation first
2. Ligands in alphabetical order
3. Metal name with oxidation state in Roman numerals
4. Anionic complex: Latin metal name + -ate suffix
5. Determine oxidation state: metal charge = complex charge − sum of ligand charges

Practise naming the 5 examples in this article from scratch, then try 5 more from NCERT. Target: any complex named correctly in under 90 seconds.

Step 3 — Draw and understand the CFT splitting diagram (Day 2–3) Draw the octahedral splitting diagram (t₂g lower, e_g higher) and the tetrahedral diagram (e lower, t₂ higher) from memory. Know the spectrochemical series from CN⁻/CO (strongest) to I⁻/Br⁻ (weakest). Practice: given a d-electron count and a ligand, determine high-spin vs low-spin and count unpaired electrons.

Step 4 — Classify all isomerism types (Day 3) Make a table with all isomerism types — structural (ionisation, hydrate, linkage, coordination) and stereo (geometrical, optical). For each type, know one example complex and the diagnostic condition. Geometrical isomerism in square planar (MA₂B₂) and optical isomerism in [M(en)₃]ⁿ⁺ complexes are the two most tested stereo-isomerism scenarios.

Step 5 — Solve PYQs year-wise from 2024 to 2017 (Day 4–5) Work through all NEET Coordination Compounds PYQs year by year. Each question maps to one of the six key areas identified in this article. After 5 years of PYQs, you will have seen every important question template — and the chapter will feel completely predictable.

Access the complete NEET chapter-wise PYQ collection on eSaral for all years in one place. Timed practice under exam conditions is available on the eSaral NEET Test Series.

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