CBSE Class 12 Chemistry Coordination Compounds MCQs Set H

Question. What will be the correct order of absorption of wavelength of light in the visible region for the complexes, [Co(NH₃)₆]³⁺, [Co(CN)₆]^3–,[Co(H₂O)₆]³⁺ ?
(a) [Co(CN)₆]^3– > [Co(NH₃)₆]³⁺ > [Co(H₂O)₆]³⁺
(b) [Co(NH₃)₆]³⁺ > [Co(H₂O)₆]³⁺ > [Co(CN)₆]^3–
(c) [Co(H₂O)₆]³⁺ > [Co(NH₃)₆]³⁺ > [Co(CN)₆]^3–
(d) [Co(CN)₆]^3– > [Co(H₂O)₆]³⁺ > [Co(NH₃)₆]³⁺
Answer: c

Question. The formula of the complex diamminechlorido (ethylenediamine)nitroplatinum(IV) chloride is
(a) [Pt(NH₃)₂Cl(en)NO₂]Cl₂
(b) Pt[Pt(NH₃)₂(en)Cl₂NO₂]
(c) Pt[(NH₃)₂(en)NO₂]Cl₂
(d) Pt[(NH₃)₂(en)NO₂Cl₂]
Answer: a

Question. Which of the following is correct?
(a) Valence bond theory explains the colour of the coordination compounds.
(b) [NiCl₄]^2– is diamagnetic in nature.
(c) EDTA is a chelating ligand.
(d) A bidentate ligand can have four coordination sites.
Answer: c

Question. According to Werner’s theory of coordination compounds,
(a) primary valency is ionisable
(b) secondary valency is ionisable
(c) primary and secondary valencies are ionisable
(d) neither primary nor secondary valency is ionisable.
Answer: a

Question. The increasing order of crystal field splitting strength of the given ligands is
(a) NH₃ < Cl^– < CN^– < F^– < CO < H₂O
(b) F^– < Cl^– < NH₃ < CN^– < H₂O < CO
(c) Cl^– < F^– < H₂O < NH₃ < CN^– < CO
(d) CO < CN– < NH₃ < H₂O < F^– < Cl^–
Answer: d

Question. Correct formula of tetraamminechloridonitroplatinum( IV) sulphate can be written as
(a) [Pt(NH₃)₄(ONO)Cl]SO₄
(b) [Pt(NH₃)₄Cl₂NO₂]₂SO₄
(c) [Pt(NH₃)₄(NO₂)Cl]SO₄
(d) [PtCl(ONO)NH₃(SO₄)]
Answer: c

Question. The name of [Co(NH₃)₅NO₂]Cl₂ will be
(a) pentaamminonitrocobalt(II) chloride
(b) pentaamminenitrochloridecobaltate(III)
(c) pentaamminenitrito-N-cobalt(III) chloride
(d) pentanitrosoamminechlorocobaltate(III).
Answer: c

Question. Copper sulphate dissolves in ammonia due to the formation of
(a) Cu₂O
(b) [Cu(NH₃)₄]SO₄
(c) [Cu(NH₃)₄]OH
(d) [Cu(H₂O)₄]SO₄
Answer: b

Question. When one mole of each of the following complexes is treated with excess of AgNO₃ which will give maximum amount of AgCl?
(a) [Co(NH₃)₆]Cl₃
(b) [Co(NH₃)₅Cl]Cl₂
(c) [Co(NH₃)₄Cl₂]Cl
(d) [Co(NH₃)₃Cl₃]
Answer: a

Question. Which of the following complexes will show maximum paramagnetism?
(a) 3d⁴
(b) 3d⁵
(c) 3d⁶
(d) 3d⁷
Answer: b

Question. Hexaamminenickel(II) hexanitrocobaltate(III) can be written as
(a) [Ni(NH₃)₆][Co(NO₂)₆]
(b) [Ni(NH₃)₆]₃[Co(NO₂)₆]₂
(c) [Ni(NH₃)₆] [Co(NO₂)₆]
(d) [Ni(NH₃)₆(NO₂)₆]Co
Answer: b

Question. Identify the statement which is not correct?
(a) Coordinate compounds are mainly known for transition metals.
(b) Coordination number and oxidation state of a metal are same.
(c) Tetrahedral complexes form low spin complex.
(d) A ligand donates at least one electron pair to the metal atom to form a bond.
Answer: b

Question. The magnitude of magnetic moment (spin only) of [NiCl₄]^2– will be
(a) 2.82 B.M.
(b) 0
(c) 1.23 B.M.
(d) 5.64 B.M.
Answer: a

Question. Which of the following is not a neutral ligand?
(a) H₂O
(b) NH₃
(c) ONO
(d) CO
Answer: c

Question. In which of the following compounds, the transition metal is in oxidation state of zero?
(a) [Fe(H₂O)₃(OH)₃]
(b) [Ni(CO)₄]
(c) [Fe(H₂O)₆]SO₄
(d) [Co(NH₃)₆]Cl₃
Answer: b

Question. Which of the following shall form an octahedral complex?
(a) d ⁴(low spin)
(b) d ⁸(high spin)
(c) d ⁶(low spin)
(d) None of these
Answer: d

Question. The number of unpaired electrons in [Ni(CO)₄] is
(a) one
(b) two
(c) three
(d) zero
Answer: d

Question. Which of the following is a tridentate ligand?
(a) EDTA^4–
(b) (COO)₂^2–
(c) dien
(d) NO₂ ^–
Answer: c

Question. A substance appears coloured because
(a) it absorbs light at specific wavelength in the visible part and reflects rest of the wavelengths
(b) ligands absorb different wavelengths of light which give colour to the complex
(c) it absorbs white light and shows different colours at different wavelength
(d) it is diamagnetic in nature.
Answer: a

Question. Among the following, which are ambidentate ligands?
(i) SCN^–
(ii) NO₃^–
(iii) NO₂^–
(iv) C₂O₄^2–
(a) (i) and (iii)
(b) (i) and (iv)
(c) (ii) and (iii)
(d) (ii) and (iv)
Answer: a

Question. Some details of few Nickel complexes are given below:
Complex I : Diamagnetic and square planar
Complex II : Paramagnetic and tetrahedral
Complex III : Diamagnetic and tetrahedral
Complex IV : Paramagnetic and Octahedral
Which is not correct option for the given complexes?
(a) The ligand in complex I is CN^– and it has dsp² hybridisation.
(b) The ligand in complex II is Cl^– and it has sp³ hybridisation.
(c) The ligand in complex IV is H₂O and it has d²sp³ hybridisation.
(d) The ligand in complex III is CO and it has sp³ hybridiation.
Answer: c

Question. Arrange the following complexes in increasing order of conductivity of their solutions.
(i) [Co(NH₃)₃Cl₃]
(ii) [Co(NH₃)₄Cl₂]Cl
(iii) [Co(NH₃)₆]Cl₃
(iv) [Co(NH₃)₅Cl]Cl₂
(a) (i) < (ii) < (iv) < (iii)
(b) (ii) < (i) < (iii) < (iv)
(c) (i) < (iii) < (ii) < (iv)
(d) (iv) < (i) < (ii) < (iii)
Answer: a

Case Based MCQs

Case I : Read the passage given below and answer the following questions.

Werner, a Swiss chemist in 1892 prepared and characterised a large number of coordination compounds and studied their physical and chemical behaviour. He proposed that, in coordination compounds, metals possess two types of valencies, viz. primary valencies, which are normally ionisable and secondary valencies which are non-ionisable. In a series of compounds of cobalt (III) chloride with ammonia, it was found that some of the chloride ions could be precipitated as AgCl on adding excess of AgNO3 solution in cold, but some remained in solution. The number of ions furnished by a complex in a solution can be determined by precipitation reactions. The measurement of molar conductance of solutions of coordination compounds helps to estimate the number of ions furnished by the compound in solution.

In the following questions, a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices on the basis of the above passage.
(a) Assertion and reason both are correct statements and reason is correct explanation for assertion.
(b) Assertion and reason both are correct statements but reason is not correct explanation for assertion.
(c) Assertion is correct statement but reason is wrong statement.
(d) Assertion is wrong statement but reason is correct statement.

The following questions are multiple choice questions. Choose the most appropriate answer :

Question. Assertion : The complex [Co(NH₃)₄Cl₂]Cl gives precipitate corresponding to 2 mol of AgCl with AgNO₃ solution.
Reason : It ionises as [Co(NH₃)₄Cl₂]⁺ + Cl^–.
Answer: d

Question. Assertion : The complex [Co(NH₃)₃Cl₃] does not give precipitate with silver nitrate solution.
Reason : The given complex is non-ionisable.
Answer: a

Question. Assertion : CoCl₃⋅3NH₃ is not conducting while CoCl₃⋅5NH₃ is conducting.
Reason : The complex of CoCl₃⋅3NH₃ is [CoCl₃(NH₃)₃] while that of CoCl₃⋅5NH₃ is [CoCl(NH₃)₅]Cl₂.
Answer: a

Question. Assertion : CoCl₃⋅4NH₃ gives 1 mol of AgCl on reacting with AgNO₃, its secondary valency is 6.
Reason : Secondary valency corresponds to coordination number.
Answer: b

Question. Assertion : 1 mol of [CrCl₂(H₂O)₄]Cl ⋅ 2H₂O will give 1 mol of AgCl on treating with AgNO₃.
Reason : Cl– ions satisfying secondary valanceis will not be precipitated.
Answer: a

Read the passage given below and answer the following questions.

Coordination compounds are formulated and named according to the IUPAC system.
Few rules for naming coordination compounds are :
(I) In ionic complex, the cation is named first and then the anion.
(II) In the coordination entity, the ligands are named first and then the central metal ion.
(III)When more than one type of ligands are present, they are named in alphabetical order of preference without any consideration of charge.

Question. The IUPAC name of [Ni(CO)₄] is
(a) tetracarbonylnickel(II)
(b) tetracarbonylnickel(0)
(c) tetracarbonylnickelate(II)
(d) tetracarbonylnickelate(0).
Answer: b

Question. Correct formula of pentaamminenitrito-Ocobalt( III) sulphate is
(a) [Co(NO₂)(NH₃)₅]SO₄
(b) [Co(ONO)(NH₃)₅]SO₄
(c) [Co(NO₂)(NH₃)₄](SO₄)₂
(d) [Co(ONO)(NH₃)₄](SO₄)₂
Answer: b

Question. As per IUPAC nomenclature, the name of the complex [Co(H₂O)₄(NH₃)₂]Cl₃ is
(a) tetraaquadiamminecobalt(II) chloride
(b) tetraaquadiamminecobalt(III) chloride
(c) diamminetetraaquacobalt(II) chloride
(d) diamminetetraaquacobalt(III) chloride.
Answer: d

Question. The IUPAC name of the complex [Pt(NH₃)₃Br(NO₂)Cl]Cl is
(a) triamminechlorobromonitroplatinum(IV) chloride
(b) triamminebromonitrochloroplatinum(IV) chloride
(c) triamminebromidochloridonitroplatinum (IV) chloride
(d) triamminenitrochlorobromoplatinum(IV) chloride.
Answer: c

Question. Which of the following represents correct formula of dichloridobis(ethane-1, 2-diamine) cobalt(III) ion?
(a) [CoCl₂(en)]²⁺
(b) [CoCl₂(en)₂]²⁺
(c) [CoCl₂(en)]⁺
(d) [CoCl₂(en)₂]⁺
Answer: d

Read the passage given below and answer the following questions.

To explain bonding in coordination compounds various theories were proposed. One of the important theory was valence bond theory. According to that, the central metal ion in the complex makes available a number of empty orbitals for the formation of coordination bonds with suitable ligands. The appropriate atomic orbitals of the metal hybridise to give a set of equivalent orbitals of definite geometry.
The d-orbitals involved in the hybridisation may be either inner d-orbitals i.e., (n – 1)d or outer d-orbitals i.e., nd.
For example, Co³⁺ forms both inner orbital and outer orbital complexes, with ammonia it forms [Co(NH₃)₆]³⁺ and with fluorine it forms [CoF₆]^3– complex ion.

Question. Which of the following is an inner orbital or low spin complex?
(a) [Ni(H₂O)₆]³⁺
(b) [FeF₆]^3–
(c) [Co(CN)₆]^3–
(d) [NiCl₄]^2–
Answer: c

Question. Which of the following is true for [Co(NH₃)₆]³⁺ ?
(a) It is an octahedral, dimagnetic and outer orbital complex.
(b) It is an octahedral, paramagnetic and outer orbital complex.
(c) It is an octahedral, paramagnetic and inner orbital complex.
(d) It is an octahedral, dimagnetic and inner orbital complex.
Answer: d

Question. Which of the following is not true for [CoF₆]^3–?
(a) It is paramagnetic.
(b) It has coordination number of 6.
(c) It is outer orbital complex.
(d) It involves d²sp³ hybridisation.
Answer: d

Question. The paramagnetism of [CoF₆]^3– is due to
(a) 3 electrons
(b) 4 electrons
(c) 2 electrons
(d) 1 electron.
Answer: b

Assertion & Reasoning Based MCQs

For question, a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.
(a) Assertion and reason both are correct statements and reason is correct explanation for assertion.
(b) Assertion and reason both are correct statements but reason is not correct explanation for assertion.
(c) Assertion is correct statement but reason is wrong statement.
(d) Assertion is wrong statement but reason is correct statement.

Question. Assertion : [Ti(H₂O)₆]³⁺ is coloured while [Sc(H₂O)₆]³⁺ is colourless.
Reason : d – d transition is not possible in [Sc(H₂O)₆]³⁺.
Answer: a

Question. Assertion : All the octahedral complexes of Ni²⁺ must be outer orbital complexes.
Reason : Outer orbital octahedral complexes are given by weak ligands.
Answer: b

Question. Assertion : Low spin complexes have less number of unpaired electrons.
Reason : [FeF₆]^3– is a low spin complex.
Answer: c

Question. Assertion : The second and third transition series elements have lesser tendency to form low spin complex as compared to the first transition series.
Reason : The CFSE (Do) is more for 4d and 5d.
Answer: d

Question. Assertion : The [Ni(en)₃]Cl₂ (en = ethylenediamine) has lower stability than [Ni(NH₃)₆]Cl₂.
Reason : In [Ni(en)₃]Cl₂ the geometry of Ni is octahedral.
Answer: d

Question. Assertion : Thiocarbonyl is a neutral ligand.
Reason : Thiocarbonyl has three donor atoms but behaves as a bidentate ligand.
Answer: c

Question. Assertion : Cu(OH)₂ is soluble in NH₄OH but not in NaOH.
Reason : Cu(OH)₂ forms a soluble complex with NH₃.
Answer: a

Question. Assertion : The ligand N₃^– is named as nitride.
Reason : N₃^– is derived from HN₃.
Answer: d

Question.Assertion : Ethylenediaminetetraacetate ion forms an octahedral complex with the metal ion.
Reason : It has six donor atoms which coordinate simultaneously to the metal ion.
Answer: a

Question. Assertion : [Fe(CN)₆]^3– has d²sp³ type hybridisation.
Reason : [Fe(CN)₆]^3– ion shows magnetic moment corresponding to two unpaired electrons.
Answer: c

Question. Assertion : [CrCl₂(H₂O)₄]NO₃ is dichlorotetraaquachromium(III) nitrate.
Reason : In writing the name of the complex cation is written first followed by the anion.
Answer: d

Question. Assertion : [Pt(NH₃)₂Cl₂] is square planar.
Reason : The oxidation state of platinum is + 2.
Answer: b

Question. Assertion : [Al(NH₃)₆]³⁺ does not exist in aqueous solution.
Reason : NH₃ is a neutral ligand.
Answer: b

Question. Assertion : [Fe(CN)₆]^3– is weakly paramagnetic while [Fe(CN)₆]^4– is diamagnetic.
Reason : [Fe(CN)₆]^3– has +3 oxidation state while [Fe(CN)₆]^4– has +2 oxidation state.
Answer: b