Coordination Compounds

35 solved questions from Class 12 Chemistry, each with the full working. Tap any question to see the step-by-step solution.

• 1 What is the primary chemical reaction or bonding mechanism highlighted in 'Coordination Compounds' (Class 12)? medium MCQ Reaction Mechanism & Bonding
• 2 What factor affects the rate or equilibrium constant of reactions in 'Coordination Compounds'? medium MCQ Chemical Kinetics & Factors
• 3 Which functional group or IUPAC nomenclature rule applies to compounds in 'Coordination Compounds'? medium MCQ IUPAC Nomenclature & Structure
• 4 What is the major product obtained in the characteristic reaction of 'Coordination Compounds'? medium MCQ Reaction Products & Selectivity
• 5 Which class of ligand does the ammonia molecule NH3 belong to when it coordinates to a metal ion? easy 1 mark Ligand classification
• 6 Calculate the crystal field stabilization energy (CFSE) in kJ mol⁻¹ for the octahedral complex [Fe(CN)₆]⁴⁻, given that the octahedral splitting parameter Δ₀ = 20 000 cm⁻¹. Assume low-spin configuration. hard 4 marks Crystal field stabilization energy calculation
• 7 How many geometrical isomers are possible for the octahedral complex [Co(en)3]3+ where en = ethylenediamine? medium MCQ 2 marks Isomerism in coordination complexes
• 8 Which type of ligand is the water molecule (H₂O) when it acts as a donor to a metal ion in a coordination compound? easy MCQ 1 mark Ligand classification (L‑type)
• 9 Write the correct IUPAC name for the complex [Cr(NH_3)_4Cl_2]Cl· H_2O. medium 2 marks Naming of coordination compounds (IUPAC)
• 10 Discuss the factors that influence the rate of substitution reactions in octahedral coordination complexes. Illustrate your answer with the substitution of the chloride ligand in [Co(NH_3)_5Cl]^2+ by water, indicating the type of mechanism and why the reaction is relatively slow. hard 4 marks Kinetics of substitution in coordination compounds
• 11 The octahedral complex [Co(NH₃)₆]³⁺ has a high–spin d⁶ configuration and an octahedral field splitting parameter Δ₀ = 15 000 cm⁻¹. Calculate the crystal field stabilization energy (CFSE) in kJ mol⁻¹ for this complex. (Use 1 cm⁻¹ = 0.01196 kJ mol⁻¹). hard 4 marks Crystal field stabilization energy (CFSE)
• 12 Cyanide ion (CN⁻) can bind to a metal ion through either the carbon or nitrogen atom. Which type of ligand does CN⁻ represent when it donates an electron pair to a metal ion in a coordination compound? easy MCQ 1 mark Ligand classification
• 13 Determine the total number of stereoisomers (including optical isomers) that can exist for the complex ion [Co(en)₂Cl₂]⁺, where en = ethylenediamine. hard 5 marks Stereochemistry of coordination compounds
• 14 Calculate the crystal field stabilization energy (CFSE) of the octahedral complex [Fe(H_2O)_6]^2+ given that the octahedral splitting parameter Δ_o=12 000 cm^-1. Assume a high‑spin d^6 configuration. (Use 1 cm^-1=0.01196 kJ mol^-1.) medium 2 marks CFSE calculation for high‑spin octahedral complexes
• 15 Explain why the substitution of the chloride ligand in [Co(NH_3)_5Cl]^2+ by water occurs very slowly. In your answer, discuss the electronic configuration, the type of substitution mechanism, write the overall balanced reaction, and give the rate law for this reaction. hard 5 marks Kinetics and mechanism of substitution in octahedral complexes
• 16 How many geometrical isomers (including any possible optical isomers) can exist for the octahedral complex [M(NH_3)_2Cl_2(H_2O)_2] where the two NH_3, two Cl, and two H_2O ligands are each identical? medium 2 marks Geometrical isomerism in $MA_{2}B_{2}C_{2}$ octahedral complexes
• 17 In the complex ion [Co(NO_2)_6]^3-, the nitrite ligand can bind to the metal either through nitrogen or through oxygen. How is such a ligand classified? easy MCQ 1 mark Ambidentate ligand classification
• 18 How many distinct stereoisomers (including optical isomers) are possible for the octahedral complex [M(NH₃)₄Cl₂] where M = Fe³⁺ and the two Cl ligands are identical while the four NH₃ ligands are identical? medium 3 marks Stereochemistry of coordination complexes
• 19 What type of ligand is water (H₂O) when it acts as a donor to a metal ion in a coordination compound? easy 1 mark Ligand classification
• 20 The complex ion [Fe(bipy)₅Br]³⁺ (bipy = 2,2′-bipyridine) undergoes substitution of the bromide ligand by water. Write the balanced reaction, describe the mechanism of substitution, and give the rate law for this reaction. hard 4 marks Substitution mechanism and kinetics
• 21 Calculate the crystal field stabilization energy (CFSE) in kJ mol⁻¹ of the high‑spin octahedral complex [Fe(H₂O)₆]³⁺ (d⁵) given Δ₀ = 14 000 cm⁻¹. Use 1 cm⁻¹ = 0.01196 kJ mol⁻¹. medium 2 marks CFSE calculation
• 22 The ligand nitrite (NO_2^-) can coordinate to a metal ion either through nitrogen or through oxygen. According to IUPAC classification, such a ligand is called: easy MCQ 1 mark ligand classification
• 23 Calculate the crystal field stabilization energy (CFSE) in kJ mol^-1 for the low‑spin octahedral complex [Co(CN)_6]^3- (Co^3+, d^6) given Δ_o=18 000 cm^-1. Use 1 cm^-1=0.01196 kJ mol^-1. medium 2 marks CFSE calculation for low‑spin octahedral complex
• 24 How many distinct stereoisomers (including both geometrical and optical) are possible for the octahedral complex [M(AA)_2(BB)_2] where AA = ethylenediamine (en) and BB = oxalate (ox), both bidentate ligands that are identical within each type? Assume the complex is neutral and the metal is in the +2 oxidation state. hard 5 marks isomerism with two different bidentate ligands
• 25 Write the correct IUPAC name for the complex [Cr(H_2O)_4Cl_2]Cl·2H_2O. medium 2 marks nomenclature of coordination compounds
• 26 Determine the oxidation state of the metal atom in the complex ion [Ni(en)[3]^2+, where [en] is ethylenediamine (en is a neutral ligand). easy 1 mark Oxidation state calculation in coordination complexes
• 27 How many optical isomers can the octahedral complex [Co(en)[3]^3+ (where en = ethylenediamine) have? medium 2 marks Optical isomerism in octahedral complexes
• 28 Calculate the crystal field stabilization energy (CFSE) in kJ mol⁻¹ for the high‑spin octahedral complex [Cr(H₂O)₆]³⁺ (Cr³⁺, d³) given Δ₀ = 12 000 cm⁻¹. Use 1 cm⁻¹ = 0.01196 kJ mol⁻¹. medium 2 marks CFSE calculation for high‑spin d³
• 29 The complex ion [Co(phen)3]²⁺ (phen = 1,10‑phenanthroline, bidentate) undergoes substitution of one phen ligand by a water molecule to give [Co(phen)2(H₂O)₂]²⁺. Write the balanced substitution reaction, describe the substitution mechanism, and give the rate law for this reaction. hard 3 marks Substitution mechanism in coordination complexes
• 30 How many distinct stereoisomers (including optical isomers) are possible for the octahedral complex [M(phen)2Cl2] where phen is 1,10‑phenanthroline (bidentate) and Cl⁻ is monodentate, assuming the complex is neutral and the metal is in the +2 oxidation state? hard 3 marks Stereochemistry of octahedral complexes
• 31 Determine the oxidation state of manganese in the complex ion [Mn(bipy)3]2+ where bipy = 2,2'-bipyridine (neutral ligand). easy 1 mark Oxidation state determination
• 32 The nitrite ion (\text{NO}_2^-) can bind to a metal centre via either the nitrogen or the oxygen atom. According to IUPAC nomenclature, such a ligand is called: easy MCQ 1 mark Ligand classification
• 33 Determine the oxidation state of iron in the complex ion [Fe(en)_3]^2+ where en = 1,10-ethylenediamine (neutral ligand). medium 2 marks Oxidation state determination
• 34 Which of the following IUPAC terms correctly describes the ligand NO_2^- that can bind to a metal centre via either nitrogen or oxygen atom? easy MCQ 2 marks Ligand classification
• 35 Calculate the crystal field stabilization energy (CFSE) in kJ mol⁻¹ for the high‑spin octahedral complex [MnCl_6]^3- where Mn^3+ (d^4) has an octahedral field splitting Delta_0 = 10,000 cm^-1. Use 1 cm^-1 = 0.01196 kJ mol^-1. hard 4 marks Crystal field stabilization energy