Coordination Compounds Class 12 MCQ: This article presents a set of crucial Multiple Choice Questions (MCQs) for the Coordination Compounds chapter of Class 12 Chemistry. The MCQ section in CBSE Board Exams is highly scoring since each correct answer earns you 1 mark without any negative marking. However, answering MCQs can be challenging as questions may cover any part of the textbook and be based on seemingly minor concepts. MCQs are included in the CBSE exam pattern to test students’ understanding of concepts, as well as their critical and analytical thinking skills.
The MCQs provided here are excellent resources for practice, crafted by subject matter experts. They align with the revised CBSE syllabus and cover all the concepts discussed in the chapter. Practicing these MCQs can significantly aid your preparation for the CBSE Board Exam 2024.
Coordination compounds consist of a central atom surrounded by ligands, which can be anions or cations. The central atom, also known as a Lewis acid, forms coordinate bonds with neutral molecules or atoms in a fixed geometrical arrangement. Ligands donate lone pairs to the central atom to form these bonds. There are four types of ligands based on their bonding with the central atom. These compounds are used as catalysts and in qualitative and quantitative analysis, metal extraction, electroplating, photography, and dyes. They also hold biological significance.
In this article, we provide MCQs with explanations related to coordination compounds. These questions are beneficial for students preparing for board exams, JEE, NEET, or other competitive exams.
Coordination compounds are molecules with one or more metal centers bound by ligands (molecules or ions that donate electrons to the metal). These compounds can be charged or neutral. If charged, they are stabilized by counter-ions. In a complex ion, a metal ion is at the center, surrounded by molecules or ions connected via coordinate (dative covalent) bonds, though sometimes the bonding is more complex. Ligands are the molecules or ions encircling the metal ion.
By practicing these MCQs, students can reinforce their understanding of Coordination Compounds and boost their performance in exams.
Coordination Compounds Class 12 MCQ
Ques 1. Which of the following has a coordination number as a feature?
a) Coordination entity
b) Ligand
c) Central atom
d) Coordination compound
Answer: c
Explanation: The coordination number of a central metal ion in a complex, also known as the secondary valency, is defined as the number of donor atoms it is directly bound to. As a result, the coordination number is a quantity related to the metal ion.
Ques 2. Which of the following statements about coordination compounds’ bonding is incorrect?
a) Crystal Field Theory
b) VSEPR Theory
c) Valence Bond Theory
d) Molecular Orbital Theory
Answer: b
Explanation: The VSEPR Theory uses electron pairs in atoms to explain the structure of particular molecules. The theories VBT, CFT, LFT, and MOT explain the nature of bonding in coordination compounds.
Ques 3. A coordination complex’s core atom/ion is also known as ________.
a) Bronsted-Lowry acid
b) Lewis base
c) Lewis acid
d) Bronsted-Lowry base
Answer: c
Explanation: A Lewis acid is a species that has the ability to receive an electron pair. Lewis acids are all cations. It is a Lewis acid because the core atom of a coordination complex is metal and always accepts electrons.
Also Check: Important Questions for Class 12 Chemistry Chapter 9 Coordination Compounds
Ques 4. More than one sort of hybridization can occur in a complex with geometry.
a) tetrahedral
b) octahedral
c) trigonal bipyramidal
d) square planar
Answer: b
Explanation: Depending on whether the outer or inner d orbitals are engaged in hybridisation, complexes with octahedral geometry can have either sp³d² or d²sp³ hybridisation.
Ques 5. Determine which of the following statements about VBT is inaccurate.
a) It does not explain the colour of coordination compounds
b) It can distinguish between strong and weak ligands
c) It does not explain the kinetic stabilities of coordination compounds
d) It is unreliable in the prediction of geometries of 4-coordinate complexes
Answer: b
Explanation: One of VBT’s flaws is that it can’t tell the difference between weak and powerful ligands. Other options have their own set of drawbacks.
Ques 6. Which of the following determines the position of ligands in a mononuclear coordination entity’s formula?
a) Atomicity of the ligand
b) Charge on the ligand
c) The first letter in the name of the ligand
d) Denticity of the ligand
Answer: c
Explanation: The alphabetical order of the ligands in the formula of mononuclear coordination entities, including shortened ligands, is used. It is independent of the ligand’s atomicity, denticity, or charge.
Ques 7. Which of the following statements about a charged coordinating entity is correct?
a) The sign of the charge is written after the number
b) The charge of the complex ion is written in parenthesis while naming the entity
c) The charge is indicated as a subscript outside the square bracket on the right
d) The charge on the complex ion is depicted along with the counter ion
Answer: a
Explanation: The charge of a coordination entity is written outside the square brackets on the right side as a superscript with the number before the sign of charge, without the existence of the counter ion.
Ques 8. Determine the proper name for K₂[PdCl₄].
a) Potassium tetrachlorinepalladium(II)
b) Potassium tetrachloridopalladate(II)
c) Potassium tetrachloridopalladium(II)
d) Tetrachlorinepalladate(II)
Answer: b
Explanation: Because Cl is an anionic ligand, it has the suffix -o, therefore chlorido. Furthermore, because the complex ion is anionic, the metal must end in -ate, so palladate.
Ques 9. Which substance is used to determine the hardness of water using a simple titration?
a) Mg(EDTA)
b) Fe(EDTA)
c) Na₂(EDTA)
d) Co(EDTA)
Answer: c
Explanation: With EDTA, the ions Ca²⁺ and Mg²⁺ form stable complexes, and the difference in the stability constants of the Ca and Mg complexes aids in the assessment of water hardness.
Ques 10. The core atom of which of the following biologically significant coordination molecules is magnesium?
a) Vitamin B₁₂
b) Haemoglobin
c) Chlorophyll
d) Carboxypeptidase-A
Answer: c
Explanation: Chlorophyll is a coordination molecule of magnesium that is found in plants and is important for photosynthesis.
Also Check: NCERT Exemplar Class 12 Chemistry Chapter 9 Coordination Compounds
Ques 11. Fac-mer isomerism is associated with which one of the following complexes?
a) [M(AA)₂]
b) [MA₃B₃]
c) [M(AA)₃]
d) [MA₄B₂]
Answer: b
Explanation: Fac-mer isomerism is exhibited in octahedral coordination entities of the type [MA₃B₃] depending on the positions of the similar ligands.
Ques 12. The complex ions [Co(NH₃)₅(NO₂)]²⁺ and [Co(NH₃)₅(ONO)]²⁺ are called
a) Ionization isomers
b) Linkage isomers
c) Co-ordination isomers
d) Geometrical isomers
Answer: b
Explanation: Linkage isomers are coordination compounds that have the same composition but differ in the connectivity of the ligand to the metal.
Ques 13. Which type of isomerism is shown by the complex compounds [Co(NH₃)₅Br]SO₄ and [Co(NH₃)₅SO₄]Br?
a) Ionisation
b) Optical
c) Linkage
d) Coordination
Answer: a
Explanation: Ionisation isomerism occurs when the counter ion in a complex salt is itself a potential ligand and can displace a ligand which can then become the counter ion.
Ques 14. The diamagnetic species is
a) [Ni(CN)₄]²⁻
b) [NiCl₄]²⁻
c) [CuCl₄]²⁻
d) [CoF₆]³⁻
Answer: a
Explanation: [Ni(CN)₄]²⁻ is diamagnetic because it has no unpaired electrons due to the strong field ligand CN⁻ causing pairing of electrons.
Ques 15. Primary and secondary valence of Pt in [Pt(en)₂Cl₂] are
a) 4, 4
b) 4, 6
c) 6, 4
d) 2, 6
Answer: d
Explanation: The primary valence (oxidation state) is the number of ions or groups bound to the metal ion by ionic bonds. The secondary valence (coordination number) is the number of ions or groups bound to the metal ion by coordinate bonds. In [Pt(en)₂Cl₂], Pt has a primary valence of 2 and a secondary valence of 6.
Ques 16. IUPAC name of [Pt(NH₃)₃Br(NO₂)Cl]Cl is
a) triamminechlorodibromidoplatinum (IV) chloride
b) triamminechloridobromidonitrochloride-platinum (IV) chloride
c) triamminebromidochloridonitroplatinum (IV) chloride
d) triamminenitrochlorobromoplatinum (IV) chloride
Answer: c
Explanation: According to IUPAC naming, the ligands are named in alphabetical order. Therefore, bromido comes before chlorido and nitro.
Ques 17. Which of the following has square planar structure?
a) [NiCl₄]²⁻
b) [Ni(CO)₄]
c) [Ni(CN)₄]²⁻
d) None of these
Answer: c
Explanation: [Ni(CN)₄]²⁻ has a square planar structure due to dsp² hybridization.
Also Check: Coordination Compounds Class 12 Notes Chemistry Chapter 9
Ques 18. The geometry and magnetic behaviour of the complex [Ni(CO)₄] are
a) Square planar and paramagnetic
b) Tetrahedral and diamagnetic
c) Square planar and diamagnetic
d) Tetrahedral and paramagnetic
Answer: b
Explanation: [Ni(CO)₄] is tetrahedral and diamagnetic because CO is a strong field ligand causing all electrons to pair up.
Ques 19. The IUPAC name of complex ion [Fe(CN)₆]³⁻ is
a) Hexacyanidoiron(III)ion
b) Hexacyanatoferrate (III)ion
c) Hexacyanidoferrate (III)ion
d) Tricyanoiron(III)ion
Answer: c
Explanation: According to IUPAC naming, the complex anion [Fe(CN)₆]³⁻ is named hexacyanidoferrate (III) with the metal in its -ate form.
Ques 20. Which of the following is a hexadentate ligand?
a) EDTA⁴⁻
b) (COO)₂²⁻
c) en
d) NH₃
Answer: a
Explanation: EDTA⁴⁻ is a hexadentate ligand because it has six donor atoms that can bind to a metal ion.
Ques 21. Mohr’s salt is
a) Fe₂(SO₄)₃.(NH₄)₂SO₄.6H₂O
b) FeSO₄.(NH₄)₂.SO₄.6H₂O
c) MgSO₄.7H₂O
d) FeSO₄.7H₂O
Answer: b
Explanation: Mohr’s salt is a double salt of iron (II) sulfate and ammonium sulfate with six molecules of water of crystallization.
Ques 22. According to Werner’s theory of coordination compounds
a) Primary valence is ionisable
b) Secondary valence is ionisable
c) Primary and secondary valencies are ionisable
d) Neither primary nor secondary valence is ionisable
Answer: a
Explanation: According to Werner’s theory, primary valence (oxidation state) is ionisable and satisfied by negative ions, while secondary valence (coordination number) is non-ionisable and satisfied by ligands.
Ques 23. Which one of the following is an outer orbital complex and exhibits paramagnetic behaviour?
a) [Cr(NH₃)₆]³⁺
b) [Co(NH₃)₆]³⁺
c) [Ni(NH₃)₆]²⁺
d) [Zn(NH₃)₆]²⁺
Answer: c
Explanation: [Ni(NH₃)₆]²⁺ is an outer orbital complex (uses 4d orbitals) and is paramagnetic due to the presence of unpaired electrons.
Also Check: NCERT Solutions for Class 12 Chemistry Chapter 9 Coordination Compounds
Ques 24. The oxidation state of nickel in [Ni(CO)₄] is
a) 0
b) 1
c) 2
d) 3
Answer: a
Explanation: In [Ni(CO)₄], the oxidation state of nickel is 0 because CO is a neutral ligand.
Ques 25. The ligand (NH₂CH₂CH₂NH₂) is
a) bidentate
b) tridentate
c) tetradentate
d) pentadentate
Answer: a
Explanation: Ethylenediamine (en) is a bidentate ligand as it can form two bonds to a metal ion.
