Question Set C

CBSE 12th Standard Chemistry Coordination Compounds HOT Questions Study Material - QB365

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Questions:

Generic 2

4 x 2 = 8

Explain the violet colour of the complex [Ti(H₂O)₆]³⁺ on the basis of crystal field theory.

Write IUPAC names for:
(i) [Cr(NH₃)₆]³⁺
(ii) [Ni(NH₃)₆] Cl₂

Write all the geometrical isomers of [Pt(NH₃)(Br)(Cl)(py)] and how many of these will exhibit optical isomers?

Which of the two is more stable K₄[Fe(CN)₆] or K₃[Fe(CN)₆]?

Generic 3

4 x 3 = 12

(i) On the basis of crystal field theory, write the electronic configuration for d⁵ion with a strong field ligand for which ∆₀ > Ρ.
(ii) [NiCO)₄] has tetrahedral geometry, while [Ni(CN)₄]^2- has square planer yet both exhibit dimagnetism. Explain.
[Atomic number Ni = 28]

(a) How is a double salt different from a complex?
(b) Write IUPAC names of the following:
(i)K₃[Fe(C₂0₄)₃]
(ii) [Pt(NH₃)₆] Cl₄
(c) Draw the structure of cis-isomer of [Co(NH₃)₄Cl₂]⁺

Specify the oxidation numbers of the metals in the following coordination entities:
(i) [Co(H₂O) (CN) (en)₂]²⁺
(ii) [PtCl₄]^2-
(iii) [Cr(NH₃)₃Cl₃]
(iv) [CoBr₂(en)₂]⁺
(v) K₃[Fe(CN)₆]

Write the formulae for the following coordination compounds:
(a) Tetraamminediaquacobalt (III) chloride
(b) Potassium tetracyanonickelate(II)
(c) Tris(ethane-1,2-diamine) chromium (III) chloride
(d) Amminebromidochloridonirito-N-platinate (II)
(e) Dichloridobis (ethane-1, 2-diamine) platinum (IV) nitrate.
(f) Iron (III) hexacyanoferrate (II)

Multiple Choice Question

9 x 1 = 9

Structure of [Ni(CO)₄] is

(a)

tetrahedral

(b)

square planar

(c)

octahedral

(d)

None of these

10.

Which of the following are \(\pi\) - bonded organometallic compounds?

(a)

Zeise's salt

(b)

Furacene

(c)

Dibenzene chromium

(d)

Grignard reagent

11.

The spin only magnetic moment value (in Bohr magneton units) of Cr(CO)₆ is

(a)

(b)

2.84

(c)

4.90

(d)

5.92

12.

Which one of the following complex ions has geometrical isomers?

(a)

[Co(en)₃]³⁺

(b)

Ni(NH₃)₅Br]⁺

(c)

[Co(NH₃)₂(en)₂]³⁺

(d)

[Cr(NH₃)₄(en)³⁺

13.

Which of the following has largest number of isomers?

(a)

[Ru(NH₃)₄Cl₂]⁺

(b)

[Co(en)₂Cl₂]⁺

(c)

[Ir(PR₃)₂H(CO)]²⁺

(d)

[Co(NH₃)₅Cl]²⁺

14.

The formula, dichlorobis (urea) copper (II) is

(a)

[Cu{O = C(NH₂)}₂]Cl₂

(b)

[CuCl₂{O = C(NH₂)₂}]

(c)

[Cu{O = C(NH₂)₂}Cl]Cl

(d)

[CuCl₂{O = C(NH₂)₂}₂]

15.

Which of the following is an outer orbital complex?

(a)

[Fe(CN)₆]⁴^-

(b)

[FeF₆]^3-

(c)

[Co(NH₃)₆]³⁺

(d)

[Co(CN)₆]²⁺

16.

The hybridisation of Fe in K₄[Fe(CN)₆] is

(a)

dsp²

(b)

sp³

(c)

d²sp³

(d)

sp³d²

17.

An example of ambidentate ligand is

(a)

Ammine

(b)

Aquo

(c)

Oxalato

(d)

Thiacyanato

Generic 5

2 x 5 = 10

18.

Indicate the types of isomerism exhibited by the following complexes and draw the structures for these isomers:
(i) K[Cr(H₂O)₂(C₂O₄)₂
(ii) [Co(en)₃]Cl₃
(iii) [Co(NH₃)₅(NO₂)](NO₃)₂
(iv) [Pt(NH₃)(H2O)Cl₂]

19.

Using crystal field theory, draw energy level diagram, write electronic configuration of the central metal atom/ion and determine the magnetic moment value in the following :
(i) \([CoF_6]^{3-}, [Co(H_2O)_6]^{2+},[Co(CN)_6]^{3-}\)
(ii) \([FeF_6]^{3-}, \ [Fe(H_2O)_6]^{2+}, [Fe(CN)_6]^{4-}\).

Assertion and reason

2 x 1 = 2

20.

In the following question a statement of assertion followed by a statement of reasons is given. Choose the correct answer out of the following choices.
Assertion: [Cr(H₂O)₆]Cl₂ and [Fe(H₂O)₆]Cl₂ are reducing in nature.
Reasons: Unpaired electrons are present in their d-orbitals.
Codes:
(a) Assertion and reason both are true, reason is correct explanation of assertion.
(b) Assertion and reason both are true but reason is not the correct explanation of assertion.
(c) Assertion is true, reason is false.
(d) Assertion is false, reason is true.

21.

In the following questions. an Assertion (A) is followed by a corresponding Reason (R) Use the following keys to choose the appropriate answer.
Assertion (A) The ligands of nitro and nitrito are called ambidentate ligands .
Reason (R) These ligands give linkage isomers.
Codes:
(a) Both (A) and (R) are correct, (R) is the correct explanation of (A).
(b) Both (A) and (R) are correct, (R) is not the correct explanation of (A).
(c) (A) is correct; (R) is incorrect.
(d) (A) is incorrect; (R) is correct.

Case Study Questions

1 x 4 = 4

22.

Observe the diagram of splitting of d-orbitals in octahedral field and answer the questions based on the diagrams and related studied concepts.

(a) What is crystal field splitting anergy?
(b) Why d_x2-y2 ,dz²have higher energy than dxy, dyz, dzx orbitals in octahedral crystal field?
(c) What is relationship between (CFSE) \(\triangle\)₀ and strength of ligand?
(d) What is electronic configuration of d5 ion if \(\triangle\)₀ < P?
(e) What is spectrochemical series?

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Answers Key:

Generic 2

4 x 2 = 8

In ground state, Ti has 23 electrons with electronic configuration 3d³4s².
The oxidation state of Ti in the given compound is +3.
Hence it will now have the configuration 3d². Since it has 2 unpaired electrons and has the ability to
undergo d-d transition, the given complex gives violet colour.

(i) hexaamminechromium (III) ion
(ii) hexaamminenickel (II) chloride

This is a complex of the type MABCD. It will have three geometrical isomers as represented below:

It does not show optical isomerism

K₃[Fe(CN)₆] is more stable than K₄[Fe(CN)₆].

Generic 3

4 x 3 = 12

(i) On the basis of crystal field theory, for a d⁵ ion, if ∆₀ > Ρ then the complex is a high spin complex formed by the association of weak ligands with the metal ion. As a result, the fourth electron enters one of the eg orbital, thereby exhibiting the electronic configuration
\(t_{2 g}^3 e_g^1\)
(ii) Ni(CO)₄ = Ni + 4COThus Ni(CO)₄ is diamagnetic. thus according to VBT sp³ hybridization have tetrahedral geometry. In [Ni(CN)₄]²^-, there is Ni²⁺ ion for which the electronic configuration in the valence shell is 3d⁸ 4s⁰. In presence of strong field CN^- ions, all the electrons are paired up.

Double Salt	Complex Compound
They dissociate into simple ions completely when dissolved in water. e.g., KCl.MgCI₂.6H₂0	They do not dissociate into simple ions when disolved in water. [Co(NH₃)₆]CI₃

(b) (1) Potassium trioxalato ferrate (Ill) Yz
(ii) Hexammine platinum (IV) chloride.
cis - isomer of [Co(NH₃)₄CI₂]⁺

(i) x + (0) + (-1) + (0) = + 2 or x = + 3
(ii) x - 4 = -2 or x = + 2
(iii) x + 0 + 3(-1) = 0 or x = + 3
(iv) x + 2(-1) + 0 = + 1 or x = + 3
(v) [Fe(CN)₆]^3-, x + 6(-1) = - 3 or x = + 3

(a) [Co(NH₃)₄(H₂O)₂]Cl₃
(b) K₂[Ni(CN)₄]
(c) [Cr(en)₃]Cl₃
(d) [Pt(Br)(Cl)(NO₂)(NH₃)]
(e) [PtCl₂(en)₂](NO₃)₂
(f) Fe₄[Fe(CN)₆]_3-

Multiple Choice Question

9 x 1 = 9

(a)
tetrahedral

10.

(a)
Zeise's salt

11.

(a)
0

12.

13.

(b)
[Co(en)₂Cl₂]⁺

14.

(b)
[CuCl₂{O = C(NH₂)₂}]

15.

(b)
[FeF₆]^3-

16.

17.

(d)
Thiacyanato

Generic 5

2 x 5 = 10

18.

(i) Both geometrical (cis-, trans-) isomers for K[Cr(H₂O)₂(C₂O₄)₂ can exist. Also, optical isomers for cis-isomer exist.

(ii) Trans-isomer is optically inactive. On the other hand, cis-isomer is optically active.

Two optical isomers for [Co(en)₃]Cl₃exits

(iii) Two optical isomers are possible for this structure

(iv) A pair of optical isomers:

It can also show linkage isomerism.
[Co(NH₃)₅(NO₂)](NO₃)₂and [Co(NH₃)₅(ONO)](NO₃)₂
It can also show ionization isomerism.
[Co(NH₃)₅(NO₂)](NO₃)₂= [CO(NH₃)₅(NO₃)](NO₃)(NO₂)

19.

(i) \([CoF_6]^{3-}\)
\( [Co(H_2O)_6]^{2+}\)
\([Co(CN)_6]^{3-}\)
(ii) \([FeF_6]^{3-}\)
\(\ [Fe(H_2O)_6]^{2+}\)
\([Fe(CN)_6]^{4-}\)
It is diamagnetic due to the absence of unpaired electrons.

Assertion and reason

2 x 1 = 2

20.

(b) Assertion and reason both are true but reason is not the correct explanation of assertion.

21.

(a) When a monodentate ligand has two possible donor atoms and attached in two ways to the central metal atom then that ligand is called ambidentate ligand. e.g. nitro (NO₂) and nitrito (ONO). These show linkage isomerism. Both (A) and (R) are correct and (R) is the correct explanation of (A).

Case Study Questions

1 x 4 = 4

22.

(a) The energy difference between the two sets of d-orbitals is called crystal field splitting energy denoted by \(\triangle\)₀ .
(b) The orbitals dx²y², dz² lying in the direction of ligands, will experience greater repulsion and their energies will be raised relative to their positions in symmetrical field as compared to orbitals dxy, dyz, dzx lying in between the axis (at angle of 45°), lying away from the approach of ligand.
(c) Greater the (CFSE) \(\triangle\)₀ more will be strength of ligand.
(d) \(t_{2 g}^{3} e g^{2}\)
(e) The series in which ligands are arranged in increasing order of magnitude of crystal field splitting energy (\(\triangle\)₀ ) is called spectrochemical series.