Coordination compounds and the d- and p-block elements make up a large part of JEE inorganic chemistry. This set covers IUPAC naming, coordination number and oxidation state, structural and geometrical isomerism, crystal field theory, spin-only magnetic moment and EAN, then lanthanoid contraction, KMnO₄ and key p-block trends.
How to practise: read each question and tap the option you think is correct. You will see right away whether you got it, along with a short explanation, and your score is tracked at the bottom of the screen. This set has 15 questions.
Topics covered in this set
- IUPAC naming of complexes
- Coordination number, oxidation state and EAN
- Structural and geometrical isomerism
- Crystal field theory and spectrochemical series
- Magnetic moment μ = √n(n+2) BM
- Lanthanoid contraction and p-block trends
JEE Chemistry MCQs with answers and explanations
Q1. What is the IUPAC name of [Co(NH₃)₅Cl]Cl₂?
a) Pentaamminechloridocobalt(III) chloride
b) Pentaamminecobalt(III) trichloride
c) Chloridopentaamminecobalt(II) chloride
d) Pentaamminechloridocobalt(II) dichloride
Q2. What are the oxidation state and coordination number of iron in K₃[Fe(CN)₆]?
a) +2 and 6
b) +3 and 6
c) +3 and 3
d) +6 and 6
Q3. One mole of CoCl₃·6NH₃ gives 3 mol of AgCl with excess AgNO₃. What is its correct formula?
a) [Co(NH₃)₄Cl₂]Cl
b) [Co(NH₃)₃Cl₃]
c) [Co(NH₃)₆]Cl₃
d) [Co(NH₃)₅Cl]Cl₂
Q4. [Co(NH₃)₅Br]SO₄ and [Co(NH₃)₅(SO₄)]Br are examples of:
a) Linkage isomerism
b) Coordination isomerism
c) Ionisation isomerism
d) Geometrical isomerism
Q5. How many geometrical isomers does the square planar complex [Pt(NH₃)₂Cl₂] have?
a) 4
b) 2
c) 1
d) 3
Q6. An octahedral complex of the type [MA₃B₃] shows which pair of geometrical isomers?
a) cis and trans
b) fac and mer
c) syn and anti
d) d and l
Q7. Which ligand produces the largest crystal field splitting?
a) F⁻
b) H₂O
c) CN⁻
d) I⁻
Q8. What is the spin-only magnetic moment of [Fe(H₂O)₆]²⁺?
a) 0 BM
b) 2.83 BM
c) 5.92 BM
d) 4.90 BM
Q9. Why is [Fe(CN)₆]⁴⁻ diamagnetic?
a) It is tetrahedral
b) CN⁻ is a strong-field ligand that pairs all six d electrons in t₂g
c) Fe is in the +3 state
d) It has an odd number of electrons
Q10. Which ion has a spin-only magnetic moment of about 5.92 BM?
a) Mn²⁺
b) Cu²⁺
c) Zn²⁺
d) Cr³⁺
Q11. What is the effective atomic number (EAN) of iron in K₄[Fe(CN)₆]? (Fe: Z = 26)
a) 36
b) 34
c) 38
d) 30
Q12. What are the hybridisation and magnetic nature of [Ni(CN)₄]²⁻?
a) dsp², diamagnetic
b) sp³, paramagnetic
c) sp³, diamagnetic
d) dsp², paramagnetic
Q13. Zirconium (4d) and hafnium (5d) have almost identical atomic radii because of:
a) Screening by s electrons
b) Inert pair effect
c) Diagonal relationship
d) Lanthanoid contraction
Q14. In acidic medium, how many electrons does one MnO₄⁻ ion accept when it is reduced?
a) 5
b) 3
c) 1
d) 7
Q15. Which statement about group 14 elements is correct?
a) All elements prefer the +2 state equally
b) The +2 state becomes more stable down the group because of the inert pair effect
c) Carbon shows the highest tendency to form the +2 state
d) Pb⁴⁺ is more stable than Pb²⁺
Quick revision notes
- Name ligands alphabetically, then metal with oxidation state; anionic complexes end in -ate.
- Spin-only μ = √n(n+2) BM: n = 1, 2, 3, 4, 5 gives 1.73, 2.83, 3.87, 4.90, 5.92.
- Strong-field ligands (CN⁻, CO) give low-spin complexes; Δt ≈ (4/9)Δo.
- EAN = Z − oxidation state + 2 × CN.
- Lanthanoid contraction makes Zr ≈ Hf; inert pair effect stabilises Pb²⁺, Tl⁺, Bi³⁺.
Frequently asked questions
Are these JEE previous year questions?
No, they are original practice questions written to the NCERT-based JEE Main syllabus and level.
How do I decide high spin or low spin?
Compare Δo with the pairing energy. Strong-field ligands make Δo larger than the pairing energy, so electrons pair in t₂g first (low spin).
Why are most tetrahedral complexes high spin?
Δt is only about four-ninths of Δo, which is almost always smaller than the pairing energy.
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