CBSE Class 12 Chemistry Coordination Compounds Worksheet Set D

Question. The oxidation of Ni in [Ni(CO)₄] is:
(A) 0
(B) 2
(C) 3
(D) 4
Answer : A

Question. Which of the following will give a white precipitate upon reacting with AgNO₃?
(A) K₂ [Pt(en)2Cl₂]
(B) [Co(NH₃)₃Cl₃]
(C) [Cr(H₂O)₆]Cl₃
(D) [Fe(H₂O)₃Cl₃]
Answer : C

Question. The formula of the complex triamminetri(nitrito-O) cobalt (III) is:
(A) [Co(ONO)₃(NH₃)₃]
(B) [Co(NO₂)₃(NH₃)₃]
(C) [Co(ONO₂)₃(NH₃)₃]
(D) [Co(NO₂)(NH₃)₃]
Answer : A

Question. How many ions are produced from the complex [Co(NH₃)₅Cl]Cl₂ in solution?
(A) 4
(B) 2
(C) 3
(D) 5
Answer : C

Question. The coordination number of ‘Co’ in the complex [Co(en)₃]³⁺ is:
(A) 3
(B) 6
(C) 4
(D) 5
Answer : B

Question. Which of the following is the most stable complex?
(A) [Fe(CO)₅]
(B) [Fe(H₂O)₆]³⁺
(C) [Fe(C₂O₄)₃]^3–
(D) [Fe(CN)₆]^3–
Answer : C

Question. Ambidentate ligands like NO₂^– and SCN^– are:
(A) unidentate
(B) didentate
(C) polydentate
(D) has variable denticity 
Answer : D

Question. The formula of the coordination compound Tetraammineaquachloridocobalt (III) chloride is:
(A) [Co(NH₃)₄(H₂O)Cl]Cl₂
(B) [Co(NV)₄(H₂O)Cl]Cl₃
(C) [Co(NH₃)₂(H₂O)Cl]Cl₂
(D) [Co(NH₃)₄(H₂O)Cl]Cl 
Answer : A

Question. Which of the complex compounds give 2 moles of AgCl on reaction with AgNO₃?
(A) 1 mole of CoCl₃.6NH₃
(B) 1 mole of CoCl₃.5NH₃
(C) 1 mole of CoCl₃.4NH₃
(D) All of the above 
Answer : B

Question. The crystal field splitting energy for octahedral (Do) and tetrahedral (Dt) complexes is related as:

Answer : C

Question. Atomic number of Mn, Fe and Co are 25, 26, 27 respectively. Which of the following inner orbital octahedral complex ions are diamagnetic?
(A) [Co(NH₃)₆]³⁺
(B) [Mn(CN)₆]³⁻
(C) [Fe(CN)₆]³⁻
(D) None of the above 
Answer : A

Question. The colour of the coordination compounds depends on the crystal field splitting. 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(NH₃)₆]³⁺ > [Co(H₂O)₆]³⁺
Answer : C

Question. Amongst the following, the most stable complex is:
(A) [Fe(H₂O)₆]³⁺
(B) [Fe(NH₃)₆]³⁺
(C) [Fe(C2O4)3]³⁻
(D) [FeCl₆]³⁻ R
Answer : C

Question. How many ions are produced from the complex Co(NH₃)₆Cl₂ in solution?
(A) 6
(B) 4
(C) 3
(D) 2 
Answer : C

Assertion and Reason Based MCQs

Directions: In the following questions, a statement of Assertion (A) is followed by a statement of Reason (R).
Mark the correct choice as:
(A) Both (A) and (R) are true, and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but (R) is NOT the correct explanation of (A).
(C) (A) is true, but (R) is false.
(D) (A) is false, but (R) is true.

Question. Assertion (A): NF3 is weaker ligand than N(CH₃)₃.
Reason (R): NF₃ ionizes to give F– ions in aqueous solution.
Answer : B

Question. Assertion (A): [Cr(H₂O)₆]Cl₂ and [Fe(H₂O)₆]Cl₂ are reducing in nature.
Reason (R): Due to presence of unpaired electrons, complexes are reducing in nature.
Answer : B

Question. Assertion: Among [Co(NH₃)₆]³⁺ and [Co(en)₃]³⁺, coordination compound [Co(en)₃]³⁺ is a more stable complex.
Reason: en is a chelating ligand/bidentate ligand.
Answer : A

Question. Assertion (A): [Fe(CN)₆]³⁻ ion shows magnetic moment corresponding to the two unpaired electrons.
Reason (R): [Fe(CN)₆]^3– it has d²sp³ type of hybridisation.
Answer : D

Question. Assertion (A): [Cr(H₂O)₆]Cl₂ and [Fe(H₂O)₆]Cl₂ are reducing in nature.
Reason (R): Unpaired electrons are present in their d-orbitals.
Answer : B

Question. Assertion (A): Low spin tetrahedral complexes are rarely observed.
Reason (R): Crystal field splitting is less than pairing energy for tetrahedral complexes.
Answer : A

Case-based MCQs

I. Read the passage given below and answer the following questions:
The crystal field theory (CFT) is an electrostatic model which considers the metal-ligand bond to be
ionic arising purely from electrostatic interactions between the metal ion and the ligand. Ligands are
treated as point charges in case of anions or dipoles in case of neutral molecules. The five d orbitals in
an isolated gaseous metal atom/ion have same energy, i.e., they are degenerate. This degeneracy is maintained if a spherically symmetrical field of negative charges surrounds the metal atom/ ion. However, when this negative field is due to ligands (either anions or the negative ends of dipolar molecules like NH3 and H2O) in a complex, it becomes asymmetrical and the degeneracy of the d orbitals is lifted. It results in splitting of the d orbitals.
The following questions are multiple choice questions. Choose the most appropriate answer:

Question. Consider the coordination compound,
Na₂[Pt(CN)₄], identify the lewis acid.
(A) [Pt (CN)₄]^2–
(B) Na⁺
(C) Pt⁺²
(D) CN^–
Answer : C

Question. The CFSE for octahedral [CoCl₆]⁴⁻ is 18,000 cm⁻¹.
The CFSE for tetrahedral [CoCl₄]²⁻ will be
(A) 18,000 cm⁻¹
(B) 16,000 cm⁻¹
(C) 8,000 cm⁻¹
(D) 20,000 cm⁻¹
Answer : C

Question. An aqueous pink solution of cobalt(II) chloride changes to deep blue on addition of excess of HCl. This is because _____________.
(A) [Co(H₂O)₆]²⁺ is transformed into [CoCl₆]^4−.
(B) [Co(H₂O)₆]₂₊ is transformed into [CoCl₄]^2−.
(C) tetrahedral complexes have larger crystal field splitting than octahedral complex.
(D) None of the above
Answer : B

Question. A chelating agent has two or more than two donor atoms to bind to a single metal ion. Which of the following is not a chelating agent?
(A) thiosulphato
(B) oxalato
(C) glycinato
(D) ethane-1,2-diamine
Answer : A

II. Read the passage given below and answer the following questions:
According to Valence Bond Theory, the metal atom or ion under the influence of ligands can use its (n − 1)d, ns, np or ns, np, nd orbitals for hybridisation to yield a set of equivalent orbitals of definite geometry such as octahedral, tetrahedral, square planar and so on. These hybridised orbitals are allowed to overlap with the ligand orbitals that can donate electron pairs for bonding.
In these questions 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 (A): In the diamagnetic octahedral complex, [Co(NH₃)₆]³⁺, the cobalt ion is in +3 oxidation state.
Reason (R): Six pairs of electrons, one from each NH3 molecule, occupy the six hybrid orbitals.
Answer : B

Question. Assertion (A): [NiCl₄]²⁻ is an inner orbital complex.
Reason (R): An inner orbital or low spin or spin paired complex uses inner d orbitals of the metal ion for hybridisation. 
Answer : D

Question. Assertion (A): [Ni(CN)₄]^2– is square planar complexes, the hybridisation involved is dsp².
Reason (R): In [Ni(CN)₄]²⁻, nickel is in +2 oxidation state and has the electronic configuration 3d8.
Answer : B

Question. Assertion (A): The paramagnetic octahedral complex, [CoF₆]³⁻ uses outer orbital (4d) in hybridisation (sp³d²).
Reason (R): It is a high spin complex.
Answer : B

Please click on below link to download CBSE Class 12 Chemistry Coordination Compounds Worksheet Set A