2nd PUC Chemistry Question Bank Chapter 9 Co-Ordination Compounds

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Karnataka 2nd PUC Chemistry Question Bank Chapter 9 Co-Ordination Compounds

Question 1.
Write any three postulates of Werner’s theory of co-ordination compounds.
Answer:
(a) In co-ordination compounds metal atom shows two types of valencies.

  • Primary valency
  • Secondary valency.

(b) The primary valency is ionisable and are satisfied by negative ions.
(c) The secondary valency is non-ionisable and are satisfied by negative ions or neutral molecules.
(d) The primary valency is the oxidation number and secondary valency is co-ordination number of the metal atom.

2nd PUC Chemistry Question Bank Chapter 9 Co-Ordination Compounds

Question 2.
What are Ligands?
Answer:
The ions or molecules bound to the central metal atom/ion in the co-ordination entity are called Ligands.

Question 3.
What is Polydentate Ligand? Give example.
Answer:
When several donar atoms are present in a single ligand, than that ligand is said to be polydentate. Ex: EDTA4-

Question 4.
What is ambidentate Ligand? Give example.
Answer:
Ligand which can ligate through 2 different atoms is called ambidentate ligand.
2nd PUC chemistry Question Bank Chapter 9 Co-Ordination Compounds 1

Question 5.
Give reason “Ligands are lewis bases”.
Answer:
Ligands donate loan pair of electrons to the central metal atom/ion. Hence they are regarded as lewis bases.

2nd PUC Chemistry Question Bank Chapter 9 Co-Ordination Compounds

Question 6.
What is co-ordination number of a metal atom/ion in the complex compounds?
Answer:
The co-ordination number of a metal ion/atom in a complex is the number of donar atoms of the ligand to which the metal is directly bonded.

Question 7.
What are homoleptic and heteroleptic complexes? Give example.
Answer:
Complexes in which a metal is bound to only one kind of ligands are called homoleptic complexes. Ex: [Co(NH3)6]3+

Complexes in which a metal is bound to more than one kind of ligands are called heteroleptic complexes. [CO(NH3)4Cl2]+

Question 8.
State the rules for writing the IUPAC names of co-ordination [compounds.
Answer:
1. In ionic complexes cation is named first and then the anion.
2. In co-ordination entity ligands are named first then the central metal ion atom.
3. (a) Anionic ligands enc Is in ‘O’.
2nd PUC chemistry Question Bank Chapter 9 Co-Ordination Compounds 2
4. When more than one type of ligands are present, they are named in alphabetical order.
5. Prefixes di, tri, etc…. are used to indicate the number of the individual ligands in the co-ordination entity.
6. When the names of the ligands include a numerical prefix, then the terms bis, tris, tetrakis are used.
7. When the complex is cationic or neutral, the names of the metal is written without any characteristic ending. For anionic complex, the name of the central metal atom ends in ‘ate’.
2nd PUC chemistry Question Bank Chapter 9 Co-Ordination Compounds 3
8. Oxidation state of the metal atom/ion is indicated by Roman numeral in parenthesis.

2nd PUC Chemistry Question Bank Chapter 9 Co-Ordination Compounds

Question 9.
Write the IUPAC names of the following co-ordination compounds?
Answer:
1. [Pt(NH3)2Cl(NO2)]
Diamminechloridonitrito-N-platinum(II)

2. K3[Cr(C2O4)3]
Potassium trioxalatochromate(III)

3. [CoCl2(en)2] Cl
Dichloridobis-(ethylenediamine)cobalt(II) chloride

4. [CO(NH3)5(CO3)]Cl
Pentaamminecarbonatocobalt(III) chloride

5. [CO(NH3)4(H2O)Cl] Cl2
Tetraammineaquachloridocobalt(III) chloride

6. [CoCl2 (en)2]+
Dichloridob is- (ethane – 1,2-di amine)cobalt(III) ion.

7. [Ni(CO)4]
Tetracarbonylnickel(o)

8. [Ti(H2O)6]3+
Hexaaquatitanium(III) ion

9. [Co(NH3)5BrSO4
Pentaamminebromidocobalt(III) sulphate

10. [Cr(NH3)3(H2O)3]Cl3
Triamminetriaquachromium(III) chloride

11. [COCl2(NH3)4]Cl
Tetraamminedichloridocobalt(III) chloride

12. [Co[en)3]Cl3
Tris(ethane-l,2-diamine)cobalt(III) chloride

13. [Pt(NH3)5Cl]Br
Pentaamminechloridoplatinum(II) bromide

14. K2[Zn(OH)4]
Potassium tetrahydraxidozincate(II).

2nd PUC Chemistry Question Bank Chapter 9 Co-Ordination Compounds

Question 10.
Give the IUPAC name and oxidation number and co-ordination number of the following complex compounds.
Answer:
1. [CoC(en)3]3+
Tris(ethane-1,2 -diamine)cobalt(III) ion
co-ordination no.6
Oxidation no. +3

2. K4[Fe(CN)6]
Potassium hexacyanidoferrate(II)
Co-ordination no.6
Oxidation no. +2

3. [Co(C2O4)3]3-
Trioxalatocobaltate(III) ion
Co-ordination no.6
Oxidation no.+3

4. Na[Co(CO)4]
Sodium tetracarbonylcobaltate (-1)
Co-ordination no.4
Oxidation no.-1

5. [Pt(NH3)2(NO2)(Cl)2Br]
Diamminebromidodichloridonitrito-N-platinum(IV)
Co-ordination number 6
Oxidation number 4

6. K[Au(CN)4]
Potassium tetracyanidoaurate(III)
Co-ordination no.4
Oxidation number +3

7. [Co (C2O4)2 (en)]–
Ethane-1,2-diaminedioxalatocobaltate(III) ion
Co-ordination no.6
Oxidation no.+3

8. [Co(NH3)5(ONO)]Cl2
Pentaamminenitrito-O-Cobalt(III) chloride
Co-ordination no.6
Oxidation no.3

9. K[Pt(Cl)3 NH3]
Potassium amminetrichloridoplatinate(II)
Co-ordination no.4
Oxidation no.2

10. [Co(Br)2(en)2]Cl
Dibromidobis-(Ethane-l,2-diamine)cobalt(III) chloride
Co-ordination no.6
Oxidation no. +3

11. [CrCl2(H2O)4]NO3
Tetraaquadichloridochromium(III) nitrate
Co-ordination no.6
Oxidation no.+3

12. [Co(CO3) (NH3)5]Cl
Pentaamminebromidocobalt(III) chloride
Co-ordination no.6
Oxidation no.+3

13. [FeCl2 (en)2]Cl
Dichloridobis-(ethylenediamine)iron(III) chloride
Co-ordination no.6
Oxidation no. 3

2nd PUC Chemistry Question Bank Chapter 9 Co-Ordination Compounds

Question 11.
Write IUPAC name and ionisation isomer of [Co(NH3)5Br]SO4.
Answer:
Pentaamminebromidocobalt (III) sulphate.
Ionisation isomer [Co(NH3)5SO4]Br.

Question 12.
What is geometrical isomerism?
Answer:
In heteroleptic complexes, due to different possible geometric arrangements of the ligands around central metal ion is called geometric isomers and the phenomenon is called geometric isomerism.

Question 13.
Draw gthe cis and trans isomers of [Pt(NH3)2Cl2]
Answer:
2nd PUC chemistry Question Bank Chapter 9 Co-Ordination Compounds 4

Question 14.
Draw the cis and trans isomers of [CO(NH3)4Cl2]+.
Answer:
2nd PUC chemistry Question Bank Chapter 9 Co-Ordination Compounds 5

2nd PUC Chemistry Question Bank Chapter 9 Co-Ordination Compounds

Question 15.
Draw the structures of geometrical isomers of [Fe(NH3)2(CN)]4.
Answer:
2nd PUC chemistry Question Bank Chapter 9 Co-Ordination Compounds 6

Question 16.
Draw the geometrical isomers of [CoCl2(en)2]+
Answer:
2nd PUC chemistry Question Bank Chapter 9 Co-Ordination Compounds 7

Question 17.
Give the facial (fae) and meridional (mer) isomeric structures of [Co(NH3)3(NO2)3]
Answer:
2nd PUC chemistry Question Bank Chapter 9 Co-Ordination Compounds 8

2nd PUC Chemistry Question Bank Chapter 9 Co-Ordination Compounds

Question 18.
Draw the optical isomers of [CO(en)3]3+
Answer:
2nd PUC chemistry Question Bank Chapter 9 Co-Ordination Compounds 9

Question 19.
Draw the optical isomers of [Pt(Cl)2(en)2]2+.
Answer:
2nd PUC chemistry Question Bank Chapter 9 Co-Ordination Compounds 10

Question 20.
Draw the optical isomers of [CrCl2(ox)2]3-.
Answer:
2nd PUC chemistry Question Bank Chapter 9 Co-Ordination Compounds 11

Question 21.
Explain ionisation isomerism with an example.
Answer:
Two or more complex compounds have the same molecular formula but ionize in water to form different ions are called ionisation isomers and the phenomenon is called ionisation isomerism.
Ex: [Co(NH3)5SO4]Br
Pentaamminesulphatocobalt(III) bromide
[Co(NH3)5Br]SO4
Pentaammmcbromidocobalt(llf) sulphate.

2nd PUC Chemistry Question Bank Chapter 9 Co-Ordination Compounds

Question 22.
What is linkage isomerism? Give example.
Answer:
Two or more co-ordination compounds which have same molecular formula but differs in the mode of attachment of ambident ligand to the central metal ion.
Ex: [Co(NH3)5(NO2)]Cl2
Pentaamminenitrito-N-cobalt(III) chloride
Ex: [Co(NH3)5(ONO)]Cl2
Pentaamminenitrito-O- chloride.

Question 23.
What is an ambidentate ligand? Name the type of structural isomerism arises when such ligand present in the complex.
Answer:

  • Ligand which can ligate through two different atoms is called ambidentate ligand.
  • Linkage isomerism.

Question 24.
Explain the hybridisation, geometry and magnetic property of [Ni(CN)4]2- ion using valence bond theory.
Answer:
1. Orbitals of Ni2+ ion
2nd PUC chemistry Question Bank Chapter 9 Co-Ordination Compounds 12

2. In presence of strong ligand CN– spin pairing takes place and dsp2 hybridisation takes place.
2nd PUC chemistry Question Bank Chapter 9 Co-Ordination Compounds 13

3. Four pairs of electrons, one from each CN– occupy the four hybrid orbitals. Thus the complex has square planar geometry and diamagnetic because of the absence of unpaired electrons.
[Ni(CN)4]2- complex orbitals.
2nd PUC chemistry Question Bank Chapter 9 Co-Ordination Compounds 14

For [Ni(CN)4]2- Complex:
1. Type of hybirdisation : dsp2
2. Geometry : Square planar
3. Magnetic property : Diamagnetic

2nd PUC Chemistry Question Bank Chapter 9 Co-Ordination Compounds

Question 25.
Explain the hybridisation, geometry and magnetic property of [Ni(Cl)4]2-.
Answer:
1. orbitals of Ni2+ ion
2nd PUC chemistry Question Bank Chapter 9 Co-Ordination Compounds 15

2. In Ni2+ ion sp3 hybridisation takes place sp3 hybrid orbitals of Ni2+
2nd PUC chemistry Question Bank Chapter 9 Co-Ordination Compounds 16

3. 4 pairs of electrons one from each, occupy the four hybrid orbitals. The complex has tetrahedral geometry and paramagnetic because of two unpaired electrons.
2nd PUC chemistry Question Bank Chapter 9 Co-Ordination Compounds 17

For [Ni(Cl)4]2- Complex:
1. Type of hybirdisation : sp2
2. Geometry : Tetrahedral
3. Magnetic property : Paramagnetic

Question 26.
Explain the hybridisation, geometry and magnetic property of [Co(NH3)6]3+ based on VBT.
Answer:
1. orbitals of Co3+ ion
2nd PUC chemistry Question Bank Chapter 9 Co-Ordination Compounds 18

2. In presence of strong ligand like NH3 electron pairing takes place and d2sp3 hybridisation takes place.
2nd PUC chemistry Question Bank Chapter 9 Co-Ordination Compounds 19

3. Six pairs of electrons, one from each NH3 molecule occupy the six hybrid orbitals, then the complex has the octahedral geometry and is diamagnetic, because of the absence of unpaired electrons.
2nd PUC chemistry Question Bank Chapter 9 Co-Ordination Compounds 20

For [Co(NH3)6]3+ Complex:
1. Type of hybridisation : d2sp3
2. Geometry : Octahedral
3. Magnetic property : Diamagnetic.

2nd PUC Chemistry Question Bank Chapter 9 Co-Ordination Compounds

Question 27.
Explain the hybridisation, geometry and magnetic property of [C0F6]3- based on VBT.
Answer:
1. orbitals of C03+ ion
2nd PUC chemistry Question Bank Chapter 9 Co-Ordination Compounds 21

2. In Co3+ ion Sp3d2 takes place
2nd PUC chemistry Question Bank Chapter 9 Co-Ordination Compounds 22

3. Six pairs of electrons, one from each F– ion occupy the six hybrid orbitals. Thus, the complex has octahedral geometry and paramagnetic in nature due to the presence of four unpaired electrons.
2nd PUC chemistry Question Bank Chapter 9 Co-Ordination Compounds 23

For [C0F6]3- Complex:
(i) Type of hybridisation : sp3d2
(ii) Geometry : Octahedral
(iii) Magnetic property : Paramagnetic.

Question 28.
Give three differences between [NiCl4]2- and [NiCN4]2- with respect to type of hybridisation, magnetic behaviour and geometry.
Answer:
2nd PUC chemistry Question Bank Chapter 9 Co-Ordination Compounds 24

Question 29.
Give two differences between [Co(NH3)6]3+ and [CoF6]3-
Answer:

[Co(NH3)6]3+ [CoF6]3-
1. Inner orbital complex. 1. Outer orbital complex.
2. Diamagnetic 2. Paramagnetic.
3. d2SP3 hybridisation. 3. SP3d2 hybridisation.

Question 30.
Which set of d-orbitals of metal ion or atom experience more repulsion in octahedral field created by the ligand.
Answer:
eg set of orbitals.

2nd PUC Chemistry Question Bank Chapter 9 Co-Ordination Compounds

Question 31.
When is linkage isomerism is possible for co-ordination compounds?
Answer:
When a co-ordination compound contains a ambidentate ligand.

Question 32.
What type of stereoisomerism exhibited by the following co-ordination compound [Co(en)3]Cl3?
Answer:
Optical isomerism.

2nd PUC Chemistry Question Bank Chapter 9 Co-Ordination Compounds

Question 33.
Explain the crystal field splitting of d-orbitals in the octahedral complexes.
Answer:
Electrons in the d-orbitals of the central metal ion will be repelled by the lone pairs of the ligand. Because of these interactions the de-generacy of d-orbitals of the metal ion is lost and these split into two sets of orbitals having different energies. This is known as crystal field splitting.
2nd PUC chemistry Question Bank Chapter 9 Co-Ordination Compounds 25