JEE Chemistry MCQs – Coordination Compounds & Organic Reactions (Free PDF)

JEE Chemistry MCQs – Coordination Compounds & Organic Reactions (FreePDF)

Boost Your JEE Chemistry Preparation with Free MCQs PDF on Coordination Compounds & Organic Reactions

Ace your JEE Main & Advanced Chemistry with our specially curated JEE Chemistry MCQs on Coordination Compounds and Organic Reactions. This FREE PDF download includes high-quality, exam-level multiple-choice questions designed to help you master two of the most important topics in the JEE syllabus. Perfect for last-minute revision, practice, and self-assessment.

✔️ Based on the latest JEE syllabus
✔️ Topic-wise MCQs with detailed answer keys
✔️ Ideal for JEE Main, JEE Advanced, and other competitive exams

Download the Free PDF now and strengthen your conceptual understanding and problem-solving skills in Coordination Chemistry and Organic Reaction Mechanisms.

Keywords: JEE Chemistry MCQs, Coordination Compounds MCQs, Organic Reactions MCQs, Free JEE Chemistry PDF, JEE Main Chemistry Questions, JEE Advanced Chemistry Practice, Organic Chemistry JEE PDF, Coordination Compounds JEE PDF

📘 MCQs on Coordination Compounds

1. The IUPAC name of [Cr(NH₃)₄Cl₂]Cl is:

(A) Tetraamminedichloridochromium(III) chloride
(B) Dichlorotetraamminechromium(III) chloride
(C) Tetraamminedichlorochromium(III) chloride
(D) Dichloridochromium(III) tetraammine chloride
✅ Answer: (A)
📌 Explanation: Ligands are named in alphabetical order; NH₃ is "ammine", Cl⁻ is "chlorido".

2. Which of the following shows optical isomerism?

(A) [Co(NH₃)₆]³⁺
(B) [Cr(en)₃]³⁺
(C) [Ni(CN)₄]²⁻
(D) [Pt(NH₃)₂Cl₂]
✅ Answer: (B)
📌 Explanation: Ethylenediamine (en) is a bidentate ligand that forms chiral complexes.

3. The geometry of [Fe(CN)₆]⁴⁻ is:

(A) Square planar
(B) Octahedral
(C) Tetrahedral
(D) Trigonal bipyramidal
✅ Answer: (B)
📌 Explanation: Coordination number is 6 → octahedral geometry.

4. Which complex is most stable according to the chelate effect?

(A) [Cu(NH₃)₄]²⁺
(B) [Cu(en)₂]²⁺
(C) [Cu(H₂O)₄]²⁺
(D) [CuCl₄]²⁻
✅ Answer: (B)
📌 Explanation: Chelates (like en = ethylenediamine) increase complex stability.

5. What is the oxidation state of cobalt in [Co(CN)₆]³⁻?

(A) +2
(B) +3
(C) 0
(D) -3
✅ Answer: (B)
📌 Explanation: CN⁻ = -1 × 6 = -6; overall charge = -3 → x – 6 = -3 → x = +3

🔬 MCQs on Organic Reactions

6. Which reaction proceeds via a carbocation intermediate?

(A) SN1
(B) SN2
(C) E2
(D) Free radical halogenation
✅ Answer: (A)
📌 Explanation: SN1 involves a two-step mechanism with carbocation formation.

7. Which compound gives a positive iodoform test?

(A) Ethanol
(B) Methanol
(C) Isopropyl alcohol
(D) Formaldehyde
✅ Answer: (C)
📌 Explanation: Methyl ketones and alcohols with -CH(OH)-CH₃ group give iodoform test.

8. The product of the Cannizzaro reaction of formaldehyde is:

(A) Methanol and formic acid
(B) Methanoic acid and ethanol
(C) Ethanal and ethanol
(D) Methanol and methanoic acid
✅ Answer: (D)
📌 Explanation: In Cannizzaro reaction, one aldehyde is oxidized, one reduced.

9. Which reagent converts alcohol to aldehyde?

(A) KMnO₄
(B) PCC
(C) NaBH₄
(D) H₂/Pd
✅ Answer: (B)
📌 Explanation: PCC (Pyridinium chlorochromate) selectively oxidizes primary alcohols to aldehydes.

10. Identify the major product of the reaction of 2-bromobutane with alcoholic KOH:

(A) 2-butanol
(B) 2-butene
(C) 1-butene
(D) Butane
✅ Answer: (B)
📌 Explanation: E2 elimination gives major alkene (Zaitsev's rule).

🧪 More MCQs – Coordination Compounds

11. The complex [Ni(CO)₄] has:

(A) dsp² hybridization and square planar shape
(B) sp³ hybridization and tetrahedral shape
(C) dsp³ hybridization and trigonal bipyramidal shape
(D) d²sp³ hybridization and octahedral shape
✅ Answer: (B)
📌 Explanation: Ni(0) is in the zero oxidation state; 4 CO ligands → sp³ tetrahedral.

12. Which of the following ligands is ambidentate?

(A) SCN⁻
(B) NH₃
(C) CN⁻
(D) H₂O
✅ Answer: (A)
📌 Explanation: SCN⁻ can coordinate via either sulfur or nitrogen → ambidentate.

13. The number of unpaired electrons in [Fe(H₂O)₆]²⁺ is:

(A) 0
(B) 2
(C) 4
(D) 6
✅ Answer: (C)
📌 Explanation: Fe²⁺ = 3d⁶ → 4 unpaired electrons in weak field ligands like H₂O.

14. Which of these exhibits linkage isomerism?

(A) [Co(NH₃)₆]³⁺
(B) [Fe(CN)₆]³⁻
(C) [Co(NO₂)(NH₃)₅]Cl₂
(D) [Ni(en)₃]²⁺
✅ Answer: (C)
📌 Explanation: NO₂⁻ can bind via N (nitro) or O (nitrito) → linkage isomerism.

🧪 More MCQs – Organic Reactions

15. Which compound will undergo the fastest SN1 reaction?

(A) 1-bromobutane
(B) 2-bromobutane
(C) tert-butyl bromide
(D) methyl bromide
✅ Answer: (C)
📌 Explanation: Tertiary carbocation formed in SN1 is most stable.

16. Which of the following undergoes aldol condensation?

(A) Formaldehyde
(B) Acetone
(C) Benzaldehyde
(D) Formic acid
✅ Answer: (B)
📌 Explanation: Aldol condensation requires α-H; acetone has it.

17. In the presence of peroxide, HBr adds to propene in:

(A) Markovnikov fashion
(B) Anti-Markovnikov fashion
(C) No addition takes place
(D) Random fashion
✅ Answer: (B)
📌 Explanation: Peroxide effect (Kharasch effect) → anti-Markovnikov addition.

18. Which of the following undergoes Hoffman rearrangement?

(A) Acetamide
(B) Acetic acid
(C) Acetone
(D) Acetonitrile
✅ Answer: (A)
📌 Explanation: Hoffman rearrangement converts amides to amines.

🧪 Additional MCQs – Coordination Compounds

19. Which of the following complexes is paramagnetic?

(A) [Ni(CN)₄]²⁻
(B) [Fe(CN)₆]⁴⁻
(C) [Co(NH₃)₆]³⁺
(D) [Ni(CO)₄]
✅ Answer: (C)
📌 Explanation: [Co(NH₃)₆]³⁺ has Co³⁺ (d⁶ low spin) but often shows paramagnetism due to ligand field strength.

20. The chelate effect is due to:

(A) Increase in entropy
(B) Decrease in enthalpy
(C) Increase in enthalpy
(D) Decrease in entropy
✅ Answer: (A)
📌 Explanation: Formation of chelates releases more molecules (ligands replaced by fewer), increasing entropy.

21. The complex ion which shows cis-trans isomerism is:

(A) [Co(NH₃)₆]³⁺
(B) [Pt(NH₃)₂Cl₂]
(C) [Fe(CN)₆]³⁻
(D) [Ni(CO)₄]
✅ Answer: (B)
📌 Explanation: Square planar complexes with two different ligands show cis-trans isomerism.

🧪 Additional MCQs – Organic Reactions

22. Which of the following is a free radical substitution reaction?

(A) Nitration of benzene
(B) Bromination of methane
(C) Friedel-Crafts alkylation
(D) Cannizzaro reaction
✅ Answer: (B)
📌 Explanation: Bromination of methane proceeds via a free radical chain mechanism.

23. Which reagent is used for the selective oxidation of primary alcohol to aldehyde without further oxidation to acid?

(A) KMnO₄
(B) PCC
(C) HNO₃
(D) Na₂Cr₂O₇
✅ Answer: (B)
📌 Explanation: PCC is a mild oxidizing agent that stops at aldehyde stage.

24. In the Hell-Volhard-Zelinsky reaction, which type of compound is halogenated?

(A) Alcohols
(B) Carboxylic acids (α-position)
(C) Aldehydes
(D) Ketones
✅ Answer: (B)
📌 Explanation: The α-hydrogen of carboxylic acids is replaced by halogen.

🧪 More MCQs – Coordination Compounds

25. Which of the following ligands is a strong field ligand according to the spectrochemical series?

(A) H₂O
(B) CN⁻
(C) F⁻
(D) OH⁻
✅ Answer: (B)
📌 Explanation: CN⁻ is a strong field ligand causing pairing of electrons and low spin complexes.

26. The complex ion [Cr(NH₃)₃Cl₃] exists in:

(A) Only meridional form
(B) Only facial form
(C) Both meridional and facial forms
(D) None of the above
✅ Answer: (C)
📌 Explanation: Octahedral complexes with three identical ligands and three different ligands can show facial (fac) and meridional (mer) isomerism.

27. The oxidation state of metal in [Fe(CO)₅] is:

(A) 0
(B) +2
(C) +3
(D) +1
✅ Answer: (A)
📌 Explanation: CO is a neutral ligand; iron oxidation state is zero.

🧪 More MCQs – Organic Reactions

28. Which of the following compounds undergoes the Cannizzaro reaction?

(A) Acetaldehyde
(B) Benzaldehyde
(C) Acetone
(D) Formaldehyde
✅ Answer: (B)
📌 Explanation: Aromatic aldehydes without α-hydrogen (like benzaldehyde) undergo Cannizzaro reaction.

29. The major product formed when 1-bromopropane reacts with sodium ethoxide in ethanol is:

(A) Propene
(B) Ethylpropane
(C) 1-ethoxypropane
(D) 2-ethoxypropane
✅ Answer: (C)
📌 Explanation: Nucleophilic substitution (SN2) produces 1-ethoxypropane.

30. The reagent used to convert an aldehyde to an alcohol is:

(A) PCC
(B) KMnO₄
(C) NaBH₄
(D) H₂SO₄
✅ Answer: (C)
📌 Explanation: NaBH₄ is a reducing agent converting aldehydes to primary alcohols.

🧪 Additional MCQs – Coordination Compounds

31. Which of the following complexes is diamagnetic?

(A) [Fe(H₂O)₆]²⁺
(B) [Co(NH₃)₆]³⁺
(C) [Ni(CN)₄]²⁻
(D) [Mn(H₂O)₆]²⁺
✅ Answer: (C)
📌 Explanation: [Ni(CN)₄]²⁻ is square planar with strong field ligand CN⁻ causing pairing → diamagnetic.

32. The coordination number of copper in [Cu(NH₃)₄]²⁺ is:

(A) 2
(B) 3
(C) 4
(D) 6
✅ Answer: (C)
📌 Explanation: 4 ligands around Cu means coordination number = 4.

33. Which statement about Werner’s coordination theory is correct?

(A) It explains the magnetic properties of complexes.
(B) It introduced the concept of coordination number.
(C) It deals with isomerism only.
(D) It applies only to organic compounds.
✅ Answer: (B)
📌 Explanation: Werner’s theory introduced coordination number and primary/secondary valence.

🧪 Additional MCQs – Organic Reactions

34. Which of the following is NOT a nucleophilic substitution reaction?

(A) Hydrolysis of alkyl halides
(B) Reaction of ammonia with alkyl halides
(C) Friedel-Crafts alkylation
(D) Reaction of Grignard reagent with alkyl halide
✅ Answer: (C)
📌 Explanation: Friedel-Crafts alkylation is electrophilic aromatic substitution.

35. Which reagent converts primary alcohol to carboxylic acid?

(A) PCC
(B) KMnO₄
(C) LiAlH₄
(D) NaBH₄
✅ Answer: (B)
📌 Explanation: KMnO₄ oxidizes primary alcohols all the way to carboxylic acids.

36. Which of the following is a characteristic reaction of aldehydes?

(A) Haloform reaction
(B) Cannizzaro reaction
(C) Grignard reaction
(D) All of the above
✅ Answer: (D)
📌 Explanation: Aldehydes undergo haloform (if methyl ketone), Cannizzaro (if no α-H), and Grignard addition.

🧪 More MCQs – Coordination Compounds

37. Which of the following is NOT an example of an ambidentate ligand?

(A) NO₂⁻
(B) SCN⁻
(C) NH₃
(D) CN⁻
✅ Answer: (C)
📌 Explanation: NH₃ coordinates only via nitrogen; it is monodentate.

38. In which complex does the metal exhibit +2 oxidation state?

(A) [Fe(CN)₆]³⁻
(B) [Co(NH₃)₆]³⁺
(C) [Ni(H₂O)₆]²⁺
(D) [Cr(NH₃)₄Cl₂]Cl
✅ Answer: (C)
📌 Explanation: Ni in [Ni(H₂O)₆]²⁺ is +2.

39. Which complex exhibits optical isomerism but not geometrical isomerism?

(A) [Co(en)₃]³⁺
(B) [Pt(NH₃)₂Cl₂]
(C) [Cr(H₂O)₄Cl₂]⁺
(D) [Ni(CN)₄]²⁻
✅ Answer: (A)
📌 Explanation: The chiral tris(ethylenediamine)cobalt(III) complex shows optical isomerism.

🧪 More MCQs – Organic Reactions

40. Which compound gives a positive Tollens’ test?

(A) Acetone
(B) Benzaldehyde
(C) Ethanol
(D) Acetic acid
✅ Answer: (B)
📌 Explanation: Tollens’ reagent detects aldehydes.

41. The major product of acid-catalyzed hydration of propene is:

(A) 1-propanol
(B) 2-propanol
(C) Propanal
(D) Propanone
✅ Answer: (B)
📌 Explanation: Markovnikov addition of H₂O across double bond.

42. Which reagent is used for the bromination of aromatic rings?

(A) Br₂/FeBr₃
(B) Br₂/AlBr₃
(C) Br₂/FeCl₃
(D) Br₂ alone
✅ Answer: (A)
📌 Explanation: Br₂ with FeBr₃ acts as a Lewis acid catalyst for electrophilic aromatic substitution.

🧪 Further MCQs – Coordination Compounds

43. Which is the correct formula of the complex where cobalt is in +3 oxidation state and coordination number is 6 with four NH₃ and two Cl ligands, and two Cl ions as counter ions?

(A) [Co(NH₃)₄Cl₂]Cl₂
(B) [Co(NH₃)₄Cl₂]Cl
(C) [Co(NH₃)₄Cl₃]Cl
(D) [Co(NH₃)₄Cl]Cl₃
✅ Answer: (A)
📌 Explanation: Co³⁺ + 4 NH₃ + 2 Cl⁻ inside complex, 2 Cl⁻ outside as counter ions.

44. Which of the following is an example of a bidentate ligand?

(A) NH₃
(B) CN⁻
(C) En (ethylenediamine)
(D) Cl⁻
✅ Answer: (C)
📌 Explanation: En has two donor atoms and binds through both to the metal.

45. In the complex [Cr(H₂O)₄Cl₂]⁺, the number of possible geometrical isomers is:

(A) 1
(B) 2
(C) 3
(D) 4
✅ Answer: (B)
📌 Explanation: cis and trans forms → 2 isomers.

🧪 Further MCQs – Organic Reactions

46. Which of the following undergoes E2 elimination most rapidly?

(A) 1-bromopropane
(B) 2-bromopropane
(C) 2-bromo-2-methylpropane
(D) 1-bromo-2-methylpropane
✅ Answer: (C)
📌 Explanation: Tertiary alkyl halides favor elimination over substitution.

47. Which reagent is used to convert a carboxylic acid to an acid chloride?

(A) SOCl₂
(B) PCl₃
(C) PCl₅
(D) All of these
✅ Answer: (D)
📌 Explanation: All three reagents convert -COOH to -COCl.

48. In the nitration of benzene, the electrophile generated is:

(A) NO₂⁺
(B) NO₂⁻
(C) NO₂ radical
(D) NO
✅ Answer: (A)
📌 Explanation: NO₂⁺ is the electrophile in aromatic nitration.

🧪 Advanced MCQs – Coordination Compounds

49. The magnetic moment of a complex with 3 unpaired electrons is approximately:

(A) 1.73 BM
(B) 3.87 BM
(C) 5.92 BM
(D) 2.83 BM
✅ Answer: (B)
📌 Explanation: Magnetic moment, μ = √(n(n+2)) BM; for n=3 → √(3×5)=√15 ≈3.87 BM.

50. The hybridization of the central metal in [Fe(CN)₆]⁴⁻ is:

(A) d²sp³
(B) sp³d²
(C) dsp²
(D) sp³
✅ Answer: (A)
📌 Explanation: CN⁻ is a strong field ligand causing low spin octahedral complex → d²sp³.

51. Which of the following is NOT a characteristic of coordination compounds?

(A) They form complexes with definite stoichiometry.
(B) They show isomerism.
(C) They conduct electricity in solid state.
(D) They can be colored due to d-d transitions.
✅ Answer: (C)
📌 Explanation: Coordination compounds conduct electricity only in solution, not in solid state.

🧪 Advanced MCQs – Organic Reactions

52. Which reagent is used for selective oxidation of secondary alcohols to ketones?

(A) PCC
(B) KMnO₄
(C) NaBH₄
(D) Jones reagent
✅ Answer: (A)
📌 Explanation: PCC oxidizes alcohols to aldehydes or ketones without overoxidation.

53. The product formed on treating an aldehyde with HCN is:

(A) Alcohol
(B) Cyanohydrin
(C) Carboxylic acid
(D) Alkene
✅ Answer: (B)
📌 Explanation: Aldehydes react with HCN to form cyanohydrins.

54. The major product of the reaction between benzene and Cl₂/FeCl₃ is:

(A) Chlorobenzene
(B) Benzyl chloride
(C) Benzene chloride
(D) Benzene chloride radical
✅ Answer: (A)
📌 Explanation: Electrophilic aromatic substitution gives chlorobenzene.

🧪 More MCQs – Coordination Compounds

55. Which of the following ligands cannot form chelate complexes?

(A) Ethylenediamine (en)
(B) Oxalate ion (C₂O₄²⁻)
(C) Ammonia (NH₃)
(D) 1,2-diaminopropane
✅ Answer: (C)
📌 Explanation: NH₃ is monodentate and cannot form chelates.

56. The number of unpaired electrons in [CoF₆]³⁻ is:

(A) 0
(B) 1
(C) 3
(D) 4
✅ Answer: (C)
📌 Explanation: F⁻ is weak field ligand → high spin complex, Co³⁺ d⁶ with 4 unpaired electrons, but one pairs → 3 unpaired.

57. The geometry of [Ni(CN)₄]²⁻ complex is:

(A) Octahedral
(B) Square planar
(C) Tetrahedral
(D) Linear
✅ Answer: (B)
📌 Explanation: Strong field CN⁻ ligand causes low-spin dsp² square planar geometry.

🧪 More MCQs – Organic Reactions

58. The product of the reaction between an alkyl halide and sodium cyanide (NaCN) is:

(A) Alcohol
(B) Nitrile
(C) Amine
(D) Alkene
✅ Answer: (B)
📌 Explanation: CN⁻ acts as nucleophile, displacing halide to form nitrile.

59. Which of the following reagents is used in the Williamson ether synthesis?

(A) Alcohol and acid chloride
(B) Alcohol and alkyl halide with base
(C) Phenol and sulfuric acid
(D) Alkene and water
✅ Answer: (B)
📌 Explanation: Alkoxide ion attacks alkyl halide in SN2 reaction to form ether.

60. The reaction of an alkene with cold, dilute KMnO₄ produces:

(A) Alkane
(B) Diol (glycol)
(C) Aldehyde
(D) Ketone
✅ Answer: (B)
📌 Explanation: KMnO₄ oxidizes alkene to vicinal diol under mild conditions.

🧪 Additional MCQs – Coordination Compounds

61. Which of the following exhibits linkage isomerism?

(A) [Co(NH₃)₅(NO₂)]²⁺
(B) [Cr(H₂O)₆]³⁺
(C) [Ni(CO)₄]
(D) [Fe(CN)₆]³⁻
✅ Answer: (A)
📌 Explanation: NO₂⁻ ligand can coordinate through N or O leading to linkage isomers.

62. The complex ion [Fe(H₂O)₆]³⁺ has:

(A) High spin octahedral geometry
(B) Low spin octahedral geometry
(C) Tetrahedral geometry
(D) Square planar geometry
✅ Answer: (A)
📌 Explanation: H₂O is a weak field ligand causing high spin octahedral complex.

63. Which metal complex shows color due to d–d transition?

(A) [Zn(NH₃)₄]²⁺
(B) [Ti(H₂O)₆]³⁺
(C) [Fe(CN)₆]³⁻
(D) Both B and C
✅ Answer: (D)
📌 Explanation: Both Ti³⁺ and Fe³⁺ complexes with partially filled d orbitals show d–d transitions.

🧪 Additional MCQs – Organic Reactions

64. Which of the following compounds does NOT undergo aldol condensation?

(A) Acetaldehyde
(B) Acetone
(C) Benzaldehyde
(D) Formaldehyde
✅ Answer: (C)
📌 Explanation: Benzaldehyde has no α-hydrogen, so it doesn’t undergo aldol condensation.

65. Which reagent is used for converting aldehydes to primary alcohols?

(A) PCC
(B) NaBH₄
(C) KMnO₄
(D) H₂SO₄
✅ Answer: (B)
📌 Explanation: NaBH₄ is a mild reducing agent converting aldehydes to primary alcohols.

66. The product of the reaction between benzene and acyl chloride (RCOCl) in presence of AlCl₃ is:

(A) Alkylbenzene
(B) Phenol
(C) Aryl ketone (acetophenone-type compound)
(D) Benzaldehyde
✅ Answer: (C)
📌 Explanation: Friedel-Crafts acylation introduces acyl group, forming aryl ketones.

🧪 More MCQs – Coordination Compounds

67. Which complex is expected to be paramagnetic?

(A) [Ni(CN)₄]²⁻
(B) [Fe(H₂O)₆]³⁺
(C) [Co(NH₃)₆]³⁺
(D) [Pt(NH₃)₄]²⁺
✅ Answer: (B)
📌 Explanation: Fe³⁺ with weak field H₂O ligands forms high spin complex with unpaired electrons → paramagnetic.

68. Which of the following ligands is classified as a neutral ligand?

(A) CN⁻
(B) NH₃
(C) Cl⁻
(D) OH⁻
✅ Answer: (B)
📌 Explanation: NH₃ does not carry a charge and donates a lone pair, hence neutral.

69. The oxidation state of cobalt in the complex [Co(CO)₄]⁻ is:

(A) +1
(B) 0
(C) -1
(D) +2
✅ Answer: (B)
📌 Explanation: CO is neutral, and the complex has a -1 charge, so Co must be 0 to balance.

🧪 More MCQs – Organic Reactions

70. The reaction of primary alkyl halide with alcoholic KOH typically gives:

(A) Alkene
(B) Alcohol
(C) Ether
(D) Alkane
✅ Answer: (A)
📌 Explanation: Elimination reaction (E2) favored with alcoholic KOH leads to alkene formation.

71. Which of the following is a characteristic reaction of aldehydes?

(A) Haloform reaction
(B) Cannizzaro reaction
(C) Grignard reaction
(D) All of the above
✅ Answer: (D)
📌 Explanation: Aldehydes can undergo all these reactions depending on the conditions and substituents.

72. Which reagent converts carboxylic acid to an alcohol?

(A) LiAlH₄
(B) PCC
(C) KMnO₄
(D) NaOH
✅ Answer: (A)
📌 Explanation: LiAlH₄ is a strong reducing agent that reduces carboxylic acids to primary alcohols.

🧪 More MCQs – Coordination Compounds

73. Which of the following complexes shows optical isomerism?

(A) [Co(NH₃)₆]³⁺
(B) [Cr(en)₃]³⁺
(C) [Pt(NH₃)₂Cl₂]
(D) [Ni(CN)₄]²⁻
✅ Answer: (B)
📌 Explanation: The tris(ethylenediamine) complex is chiral and shows optical isomerism.

74. In the complex [Fe(CN)₆]³⁻, the oxidation state of iron is:

(A) +2
(B) +3
(C) +4
(D) +6
✅ Answer: (B)
📌 Explanation: CN⁻ is a -1 ligand, 6 × (-1) = -6; complex charge is -3; so Fe + (-6) = -3 → Fe = +3.

75. The coordination number of the central metal atom in [Co(NH₃)₅Cl]²⁺ is:

(A) 4
(B) 5
(C) 6
(D) 7
✅ Answer: (C)
📌 Explanation: 5 NH₃ + 1 Cl = 6 ligands → coordination number = 6.

🧪 More MCQs – Organic Reactions

76. Which of the following reagents is used to convert an alkene into a diol?

(A) KMnO₄ (cold, dilute)
(B) Br₂ in CCl₄
(C) O₃
(D) H₂SO₄
✅ Answer: (A)
📌 Explanation: Cold dilute KMnO₄ hydroxylates alkene to vicinal diol.

77. Which compound does not undergo the Cannizzaro reaction?

(A) Benzaldehyde
(B) Formaldehyde
(C) Acetaldehyde
(D) None of the above
✅ Answer: (C)
📌 Explanation: Cannizzaro reaction requires aldehydes without α-hydrogen; acetaldehyde has α-H, so it undergoes aldol condensation instead.

78. The major product of the reaction between 2-bromopropane and KOH (aqueous) is:

(A) Propane
(B) Propan-2-ol
(C) Propene
(D) Propan-1-ol
✅ Answer: (B)
📌 Explanation: Nucleophilic substitution (SN2) occurs forming propan-2-ol.

🧪 Latest MCQs – Coordination Compounds

79. Which of the following is an example of a chelating ligand?

(A) NH₃
(B) Cl⁻
(C) Ethylenediamine (en)
(D) NO₂⁻
✅ Answer: (C)
📌 Explanation: Ethylenediamine is a bidentate ligand, forming chelate complexes.

80. The coordination number of copper in [Cu(NH₃)₄]²⁺ is:

(A) 2
(B) 3
(C) 4
(D) 6
✅ Answer: (C)
📌 Explanation: Four ammonia molecules coordinate with copper, coordination number = 4.

81. Which complex has tetrahedral geometry?

(A) [Ni(CN)₄]²⁻
(B) [Ni(CO)₄]
(C) [Co(NH₃)₆]³⁺
(D) [Fe(H₂O)₆]³⁺
✅ Answer: (B)
📌 Explanation: Ni(CO)₄ is a tetrahedral complex with dsp² hybridization.

🧪 Latest MCQs – Organic Reactions

82. Which reagent is used for the oxidation of primary alcohol to aldehyde?

(A) KMnO₄
(B) PCC
(C) LiAlH₄
(D) H₂, Pd
✅ Answer: (B)
📌 Explanation: PCC selectively oxidizes primary alcohols to aldehydes without further oxidation to acids.

83. The product of the reaction between benzene and methyl chloride in the presence of AlCl₃ is:

(A) Toluene
(B) Chlorobenzene
(C) Benzyl chloride
(D) Benzene methyl ketone
✅ Answer: (A)
📌 Explanation: Friedel-Crafts alkylation produces toluene.

84. Which compound does not undergo aldol condensation?

(A) Acetaldehyde
(B) Benzaldehyde
(C) Acetone
(D) Formaldehyde
✅ Answer: (B)
📌 Explanation: Benzaldehyde lacks α-hydrogen and cannot undergo aldol condensation.

🧪 Fresh MCQs – Coordination Compounds

85. Which of the following complexes is paramagnetic?

(A) [Ni(CN)₄]²⁻
(B) [Fe(H₂O)₆]²⁺
(C) [Co(NH₃)₆]³⁺
(D) [PtCl₄]²⁻
✅ Answer: (B)
📌 Explanation: Fe²⁺ in weak field H₂O ligands has unpaired electrons → paramagnetic.

86. The oxidation state of chromium in [Cr(H₂O)₄Cl₂]⁺ is:

(A) +2
(B) +3
(C) +4
(D) +6
✅ Answer: (B)
📌 Explanation: Water is neutral, chloride is -1; overall charge +1, so Cr = +3.

87. Which of the following ligands is ambidentate?

(A) NH₃
(B) NO₂⁻
(C) Cl⁻
(D) OH⁻
✅ Answer: (B)
📌 Explanation: NO₂⁻ can bind through N or O atoms.

🧪 Fresh MCQs – Organic Reactions

88. The reagent used to convert an alkene to an alkyl bromide is:

(A) HBr
(B) Br₂ in CCl₄
(C) H₂SO₄
(D) KMnO₄
✅ Answer: (A)
📌 Explanation: HBr adds across the double bond to form alkyl bromide.

89. Which of the following is not formed during the reaction of aldehydes with NaBH₄?

(A) Primary alcohol
(B) Secondary alcohol
(C) No reaction
(D) Both A and B
✅ Answer: (B)
📌 Explanation: Aldehydes reduce to primary alcohols, not secondary.

90. The major product of the reaction between phenol and bromine water is:

(A) Bromobenzene
(B) 2,4,6-tribromophenol
(C) Phenol bromide
(D) No reaction
✅ Answer: (B)
📌 Explanation: Phenol undergoes electrophilic substitution at ortho and para positions giving tribromophenol.

🧪 Fresh MCQs – Coordination Compounds

85. Which of the following complexes is paramagnetic?

86. The oxidation state of chromium in [Cr(H₂O)₄Cl₂]⁺ is:

(A) +2
(B) +3
(C) +4
(D) +6
✅ Answer: (B)
📌 Explanation: Water is neutral, chloride is -1; overall charge +1, so Cr = +3.

87. Which of the following ligands is ambidentate?

(A) NH₃
(B) NO₂⁻
(C) Cl⁻
(D) OH⁻
✅ Answer: (B)
📌 Explanation: NO₂⁻ can bind through N or O atoms.

🧪 Fresh MCQs – Organic Reactions

88. The reagent used to convert an alkene to an alkyl bromide is:

(A) HBr
(B) Br₂ in CCl₄
(C) H₂SO₄
(D) KMnO₄
✅ Answer: (A)
📌 Explanation: HBr adds across the double bond to form alkyl bromide.

89. Which of the following is not formed during the reaction of aldehydes with NaBH₄?

(A) Primary alcohol
(B) Secondary alcohol
(C) No reaction
(D) Both A and B
✅ Answer: (B)
📌 Explanation: Aldehydes reduce to primary alcohols, not secondary.

90. The major product of the reaction between phenol and bromine water is:

🧪 New MCQs – Coordination Compounds

91. Which of the following is a zero oxidation state complex?

(A) [Ni(CO)₄]
(B) [Fe(CN)₆]³⁻
(C) [Co(NH₃)₆]³⁺
(D) [Cu(H₂O)₄]²⁺
✅ Answer: (A)
📌 Explanation: CO is neutral, no net charge, so Ni is in oxidation state 0.

92. Which geometry does the complex [PtCl₄]²⁻ adopt?

(A) Tetrahedral
(B) Square planar
(C) Octahedral
(D) Trigonal bipyramidal
✅ Answer: (B)
📌 Explanation: Pt(II) complexes commonly form square planar geometry.

93. The complex [Co(en)₃]³⁺ exhibits:

(A) Geometrical isomerism only
(B) Optical isomerism only
(C) Both geometrical and optical isomerism
(D) No isomerism
✅ Answer: (B)
📌 Explanation: tris(ethylenediamine) complexes show optical isomerism due to chirality.

🧪 New MCQs – Organic Reactions

94. The product formed when benzene reacts with SO₃/H₂SO₄ is:

(A) Benzene sulfonic acid
(B) Phenol
(C) Benzoic acid
(D) Sulfur dioxide
✅ Answer: (A)
📌 Explanation: Electrophilic aromatic substitution leads to sulfonation forming benzene sulfonic acid.

95. The reagent used for the reduction of nitrobenzene to aniline is:

(A) Zn/HCl
(B) NaBH₄
(C) PCC
(D) KMnO₄
✅ Answer: (A)
📌 Explanation: Zn/HCl reduces nitro group to amine.

96. The major product of the reaction between an aldehyde and Grignard reagent is:

(A) Primary alcohol
(B) Secondary alcohol
(C) Tertiary alcohol
(D) Ketone
✅ Answer: (B)
📌 Explanation: Grignard adds to aldehyde forming secondary alcohol after acidic workup.

🧪 Latest MCQs – Coordination Compounds

97. The coordination number of the central atom in [Fe(CO)₅] is:

(A) 4
(B) 5
(C) 6
(D) 2
✅ Answer: (B)
📌 Explanation: Five CO ligands coordinate to Fe, so coordination number is 5.

98. Which of the following complexes is diamagnetic?

(A) [Ni(CN)₄]²⁻
(B) [Fe(H₂O)₆]³⁺
(C) [Co(H₂O)₆]²⁺
(D) [Mn(H₂O)₆]²⁺
✅ Answer: (A)
📌 Explanation: CN⁻ is a strong field ligand causing pairing of electrons in Ni complex → diamagnetic.

99. The complex [Cu(NH₃)₄]²⁺ has:

(A) Square planar geometry
(B) Tetrahedral geometry
(C) Octahedral geometry
(D) Linear geometry
✅ Answer: (B)
📌 Explanation: Cu(II) with four NH₃ ligands typically forms tetrahedral geometry.

🧪 Latest MCQs – Organic Reactions

100. The major product formed when 2-bromopropane reacts with aqueous KOH is:

(A) Propan-2-ol
(B) Propene
(C) Propane
(D) Propan-1-ol
✅ Answer: (A)
📌 Explanation: Nucleophilic substitution (SN2) replaces Br with OH forming propan-2-ol.

101. Which reagent is used for oxidation of primary alcohols to carboxylic acids?

(A) PCC
(B) KMnO₄
(C) NaBH₄
(D) LiAlH₄
✅ Answer: (B)
📌 Explanation: KMnO₄ oxidizes primary alcohols fully to carboxylic acids.

102. The product formed on reaction of benzene with Cl₂/FeCl₃ is:

(A) Chlorobenzene
(B) Benzyl chloride
(C) Benzene chloride radical
(D) 1,2-Dichlorobenzene
✅ Answer: (A)
📌 Explanation: Electrophilic substitution forms chlorobenzene.

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