QUESTION BANK
UNIT 5 COORDINATION COMPOUNDS
CLASS-12 (CBSE)
S.No. Question Year
1. In coordination compounds, metals show two types of linkages, primary and secondary. Primary valencies 2023
are ionisable and are satisfied by negatively charged ions. Secondary valencies are non-ionisable and are
satisfied by neutral or negative ions having lone pair of electrons. Primary valencies are non-directional
while secondary valencies decide the shape of the complexes.
(i) If PtCl2.2NH3 does not react with AgNO3, what will be its formula?
(ii) What is the secondary valency of [Co(en)3]3+ ?
(iii) (1) Write the formula of Iron(III)hexacyanidoferrate(II).
(2) Write the IUPAC name of [Co(NH3)5Cl] Cl2.
OR
(iii) Write the hybridization and magnetic behaviour of [Ni(CN)4]2 . [Atomic number : Ni = 28]
Answer:
(i) [Pt(NH3)2Cl2]
(ii) 6
(iii) (1) Fe4[Fe(CN)6]3
(2) Pentamminechloridocobalt(III) chloride.
OR
(iii) dsp2, diamagnetic
2. (a) Write the IUPAC names of the following : 2023
(i) [Co(NH3)5(ONO)]2+ (ii) K2[NiCl4]
OR
(b) (i) What is a chelate complex ? Give one example.
(ii) What are heteroleptic complexes? Give one example.
Write chemical equation in support of your answer.
Answer:
(a) (i) Pentaamminenitrito-O-cobalt(III) ion (ii) Potassium tetrachloridonickelate(II)
OR
(b) (i) • A complex formed by a didentate or a polydentate ligand.
• [Co(ox)3]3– (or any other suitable example)
(ii) • Complexes in which a metal is bound to more than one kind of donor groups or ligands.
• [Co (NH3)4Cl2]+ (or any other suitable example)
3. (a) Draw the geometrical isomers of [Co(en)2Cl2]2+. Which geometrical isomer of [Co(en)2Cl2]2+ is not 2023
optically active and why?
(b) Write the hybridisation and magnetic behaviour of [CoF6]3–.
[Given : Atomic number of Co = 27]
Answer:
The trans isomer is not optically active because its mirror image is superimposable.
(If the student writes charge (+2 / +1) over the isomers, award full marks).
(b) sp3d2 , paramagnetic.
4. Coordination compounds are widely present in the minerals, plant and animal worlds and are known to 2023
play many important functions in the area of analytical chemistry, metallurgy, biological systems and
medicine. Alfred Werner’s Theory postulated the use of two types of linkages (primary and secondary), by
a metal atom/ion in a coordination compound.
He predicted the geometrical shapes of a large number of coordination entities using the property of
isomerism. The Valence Bond Theory (VBT) explains the formation, magnetic behaviour and geometrical
shapes of coordination compounds. It, however, fails to describe the optical properties of these
compounds. The Crystal Field Theory (CFT) explains the effect of different crystal fields (provided by the
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QUESTION BANK
UNIT 5 COORDINATION COMPOUNDS
CLASS-12 (CBSE)
ligands taken as point charges) on the degeneracy of d-orbital energies of the central metal atom/ion.
Answer the following questions :
(i) When a coordination compound NiCl2. 6H2O is mixed with AgNO3 solution, 2 moles of AgCl are
precipitated per mole of the compound. Write the structural formula of the complex and secondary
valency for Nickel ion.
(ii) Write the IUPAC name of the ionisation isomer of [Co(NH3)5(SO4)]Cl.
(iii) Using Valence Bond Theory, predict the geometry and magnetic nature of :
(1) [Ni(CO)4]
(2) [Fe(CN)6]3
[Atomic number : Ni = 28, Fe = 26]
OR
(iii) Give reasons :
(1) Low spin tetrahedral complexes are not formed.
(2) [Co(NH3)6]3+ is an inner orbital complex whereas [Ni(NH3)6]2+ is an outer orbital complex.
[Atomic number : Co = 27, Ni = 28]
Answer:
(i) [Ni(H2O)6]Cl2, secondary valency = 6
(ii) Pentaamminechloridocobalt(III)sulphate
(iii) (1) [Ni(CO)4] - tetrahedral, diamagnetic
(2) [Fe(CN)6]3–- octahedral, paramagnetic
OR
(iii) (1) Because Δt is not sufficient for the pairing of electrons / Crystal field splitting energy (CFSE) is
not sufficient for pairing of electrons.
(2) NH3 being a strong field ligand can pair up the electrons to form d2sp3 but cannot pair up in Ni2+ as two
vacant d-orbitals are not available. Therefore sp3d2 is formed.
5. Write IUPAC names of the following coordination entities : 2023
(a) [Co(NH3)4Cl(NO2)]Cl (b) [PtCl2(en)2]2+
Answer:
(a) Tetraamminechloridonitrito-N-cobalt(III) chloride
(b) Dichloridobis(ethane-1,2-diamine)platinum(IV) ion
6. Answer any three of the following questions : 2023
(a) Explain the type of hybridization in [Fe(CN)6]3 on the basis of valence bond theory. (Given : Atomic
number of Fe = 26)
(b) Draw the geometrical isomers of [PtCl2(en)2]2+ ion.
(c) [NiCl4]2 is paramagnetic while [Ni(CO)4] is diamagnetic though both are tetrahedral. Why?
(d) Name the type of isomerism when ambidentate ligands are attached to central metal ion. Give one
example of ambidentate ligand
Answer:
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QUESTION BANK
UNIT 5 COORDINATION COMPOUNDS
CLASS-12 (CBSE)
(c) Cl- being a weak field ligand does not cause pairing of electrons and hence [NiCl4]2- is paramagnetic
while CO being a strong field ligand causes pairing of electrons therefore [Ni(CO)4] is diamagnetic.
(d) Linkage isomerism. Example, CN - / NO2-/ SCN-
7. Write IUPAC names of the following coordination entities : 2023
(a) [Cr(NH3)3(H2O)3]Cl3 (b) K3[Al(C2O4)3]
Answer:
(a) Triamminetriaquachromium (III) chloride (b) Potassium trioxalatoaluminate (III)
8. Write IUPAC names of the following : 2023
(a) [Co(en)2(H2O)(CN)]2+ (b) [Ni(NH3)6]Cl2
Answer:
(a) aquacyanidobis(ethane-1,2-diamine)cobalt(III) ion (b) hexaamminenickel(II) chloride
9. (a) Which of the following species cannot act as a ligand? Give reason. 2023
OH–, NH4+ , CH3NH2, H2O
(b) The complex [Co(NH3)5(NO2)]Cl2 is red in colour. Give IUPAC name of its linkage isomer.
Answer:
(a) NH4+ ,
Due to the unavailability of lone pair of electrons / cannot act as a Lewis base.
(b) Pentaamminenitrito-O-cobalt (III)chloride
10. (a) On the basis of crystal field theory write the electronic configuration for d5 ion with a strong field 2023
ligand for which Δo > P.
(b) [Ni(CO)4] has tetrahedral geometry while [Ni(CN)4]2– has square planar yet both exhibit dimagnetism.
Explain. [Atomic number : Ni = 28]
Answer:
(a) t2g5 eg0
(b) [Ni(CO)4] has sp3 hybridisation
[Ni(CN)4]2- has dsp2 hybridisation
In both, all electrons are paired. (or explain using V.B. theory).
11. Give the formulae of the following compounds : 2020
(a) Potassium tetrahydroxidozincate (II) (b) Hexaammineplatinum (IV) chloride
Answer:
(a) K2[Zn(OH)4] (b) [Pt(NH3)6]Cl4
12. Give the formulae of the following compounds : 2020
(a) Potassium trioxalatoaluminate (III) (b) Tetraammineaquachloridocobalt (III) chloride
Answer:
(a) K3[Al(C2O4)3] (b) [Co(NH3)4(H2O)Cl]Cl2
13. Give the formulae of the following compounds : 2020
(a) Pentaamminecarbonatocobalt (III) chloride (b) Potassium tetracyanidonickelate (II)
Answer:
(a) [Co(NH3)5(CO3)]Cl (b) K2[Ni(CN)4]
14. What type of isomerism is shown by the complex [Co(NH3)5 NO2] Cl2? 2020
Answer:
Linkage isomerism
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QUESTION BANK
UNIT 5 COORDINATION COMPOUNDS
CLASS-12 (CBSE)
15. (a) Give the IUPAC name and electronic configuration of central metal atom in terms of t 2g and eg of 2020
K4[Mn(CN)6].
(b) What is meant by ‘Chelate effect’? Give an example.
Answer:
(a) Potassium hexacyanidomangnate(II)/ Potassium hexacyanomangnate(II)
(b) Increased stability of the complex due to presence of chelating or didentate or polydentate ligands.
e.g.[Cr(en)3]3+
OR
Write the hybridisation and magnetic characters of the following complexes :
(i) [Fe(CN)6]4– (ii) [CoF6]3– (iii) [Ni(CO)4]
[Atomic number : Fe = 26, Co = 27, Ni = 28]
Answer:
(i) d2sp3,diamagnetic (ii) sp3d2, paramagnetic (iii) sp3, diamagnetic
16. (a) Write the IUPAC name and hybridisation of the complex [CoF6]3–. 2020
(Given : Atomic number of Co = 27)
(b) What type of isomerism is shown by the complex [Co(en)2Cl2]2+ ?
Name the structure of an isomer of this complex which is optically active.
Answer:
a) Hexafluoridocobaltate(III); sp3d2
b) Isomerism – Geometrical / optical, cis isomer is optically active
17. (a) How can you show that complexes [Co(NH3)5 Cl] SO4 and [Co(NH3)5 SO4] Cl are ionization isomers ? 2020
(b) Write the formula of the following complex using IUPAC norms :
Potassium trioxalatochromate (III)
Answer:
(a) On adding AgNO3, [Co(NH3)5(SO4)]Cl will give white ppt of AgCl but [Co(NH3)5Cl]SO4 doesn’t / On
adding BaCl2, [Co(NH3)5Cl] SO4 will give white ppt of BaSO4 but [Co(NH3)5(SO4)]Cl doesn’t.
(b) K3[Cr(C2O4)3] / K3[Cr(ox)3]
18. Write IUPAC name and hybridization of the following complexes : 2020
(i) [Ni(CO)4] (ii) [CoF6]3–
(Atomic number Ni = 28, Co = 27)
Answer:
(i) Tetracarbonylnickel(0); sp3 (ii) Hexafluoridocobaltate(III); sp3d2
19. Write the IUPAC name and hybridisation of the following complexes : 2020
(i) [Co(NH3)6]3+ (ii) [NiCl4]2–
(Given : Atomic number : Ni = 28, Co = 27)
Answer:
i) Hexaamminecobalt(III); d2sp3 ii) Tetrachloridonickelate(II); sp3
20. (a) Write the IUPAC name and hybridisation of the complex [Fe(CN)6]3–. 2020
(Given : Atomic number of Fe = 26)
(b) What is the difference between an ambidentate ligand and a chelating ligand ?
Answer:
(a) Hexacyanidoferrate(III) / Hexacyanoferrate(III); d2sp3
(b) Ligand which can ligate through two different atoms is called ambidentate ligand whereas di- or
polydentate ligand uses its two or more donor atoms to bind a single metal ion. / a chelating ligand forms a
more stable complex as compared to an ambidentate ligand. / chelating ligand forms a cyclic complex
while ambidentate ligand forms a non-cyclic complex.
21. Discuss the nature of bonding in metal carbonyls 2020
Answer:
The metal-carbon bond in metal carbonyls possess both σ and character. The M–C σ bond is formed
by the donation of lone pair of electrons on the carbonyl carbon into a vacant orbital of the metal. The M–
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QUESTION BANK
UNIT 5 COORDINATION COMPOUNDS
CLASS-12 (CBSE)
C bond is formed by the donation of a pair of electrons from a filled d orbital of metal into the vacant
antibonding * orbital of carbon monoxide.
22. Out of Cis–[Pt(en)2Cl2]2+ and Trans–[Pt(en2)Cl2]2+, which one isoptically active ? 2020
Answer:
Cis–[Pt(en)2Cl2]2
23. Write IUPAC name of the complex [Pt(en)2Cl2]. Draw structures of geometrical isomers for this complex. 2019
Answer:
Bis(ethan-1,2-diamine)dichloridoplatinum(II)
OR
Using IUPAC norms write the formulae for the following :
(i) Hexaamminecobalt(III) sulphate (ii) Potassium trioxalatochromate(III)
Answer:
i) [Co(NH3)6]2(SO4)3 ii) K3[Cr(ox)3]
24. Write IUPAC name of the complex [Cr(NH3)4Cl2]+. Draw structures of geometrical isomers for this 2019
complex.
Answer:
Tetraamminedichloridochromium(III) ion
OR
(i) Pentaamminenitrito-O-cobalt(III) chloride (ii) Potassium tetracyanidonickelate(II)
Answer:
i) [Co(NH3)5ONO]Cl2 ii) K2[Ni(CN)4]
3– 3+
25. Out of [CoF6] and [Co(en)3] , which one complex is 2019
(i) paramagnetic (ii) more stable
(iii) inner orbital complex and (iv) high spin complex
(Atomic no. of Co = 27)
Answer:
(i) paramagnetic: [CoF6]3– (ii) more stable : [Co(en)3]3+
(iii) inner orbital complex : [Co(en)3]3+ (iv) high spin complex : [CoF6]3–
26. Out of [CoF6]3– and [Co(C2O4)3]3–, which one complex is 2019
(i) diamagnetic (ii) more stable
(iii) outer orbital complex and (iv) low spin complex ?
(Atomic no. of Co = 27)
Answer:
(i) diamagnetic : [Co(C2O4)3]3– (ii) more stable : [CoF6]3–
(iii) outer orbital complex : [CoF6]3– (iv) low spin complex : [Co(C2O4)3]3–
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QUESTION BANK
UNIT 5 COORDINATION COMPOUNDS
CLASS-12 (CBSE)
27. Write the hybridization and magnetic character of following complexes : 2019
(i) [Fe(H2O)6]2+ (ii) [Fe(CO)5] (Atomic no. of Fe = 26)
Answer:
(i) [Fe(H2O)6]2+ : sp3d2, paramagnetic (ii) [Fe(CO)5] : sp3d, diamagnetic
28. Write IUPAC name of the complex [Co(en)2(NO2)Cl]+. What type of structural isomerism is shown by 2019
this complex ?
Answer:
Chloridobis(ethane-1,2-diamine)nitrito-N-cobalt(III) ion
Linkage isomerism
OR
Using IUPAC norms, write the formulae for the following complexes :
(a) Hexaaquachromium(III) chloride (b) Sodium trioxalatoferrate(III)
Answer:
i) [Cr(H₂O)₆]Cl₃ ii) Na₃[Fe(ox)₃]
29. Define the following terms with a suitable example of each : 2019
(a) Chelate complex (b) Ambidentate ligand
Answer:
a) A complex formed by bi or polydentate ligands with metal Example- [Co(en)3]3+
b) A ligand which can ligate through two different donor atoms. Example-SCN-
(Or any other correct example)
OR
Using IUPAC norms, write the formulae for the following complexes :
(a) Tetraamminediaquacobalt(III) chloride (b) Dibromidobis(ethane-1,2-diamine)platinum(IV) nitrate
Answer:
i) [Co(NH3)4(H2O)2]Cl3 ii) [Pt Br2(en)2](NO3)2
30. (a) Using valence bond theory, write the hybridisation and magnetic character of the complex [Fe(CN)6]4–. 2019
(Atomic no. of Fe = 26)
(b) Write the electronic configuration of d6 on the basis of crystal field theory when
(i) o < P and
(ii) o > P
Answer:
(a) d2sp3, diamagnetic
b) (i)
(ii)
31. Define the following terms with a suitable example of each : 2019
(a) Polydentate ligand (b) Homoleptic complex
Answer:
i) A ligand having several donor atoms. Example- EDTA
ii) A complex in which a metal is bound to only one kind of donor groups / ligands. Example-
[Co(NH3)6]3+
(or any other correct example)
OR
Using IUPAC norms, write the formulae for the following complexes :
(a) Potassium tri(oxalato)chromate(III) (b) Hexaaquamanganese(II) sulphate
Answer:
(i) K3[Cr(ox)3] ii) [Mn(H2O)6]SO4
32. (a) Although both [NiCl4]2– and [Ni(CO)4] have sp3 hybridisation yet [NiCl4]2– is paramagnetic and 2019
[Ni(CO)4] is diamagnetic. Give reason. (Atomic no. of Ni = 28)
(b) Write the electronic configuration of d5 on the basis of crystal field theory when
6
QUESTION BANK
UNIT 5 COORDINATION COMPOUNDS
CLASS-12 (CBSE)
(i) o < P and
(ii) o > P
Answer:
a) In [NiCl4]2-, Cl- is a weak field ligand due to which there are two unpaired electrons in 3d orbital
whereas in [Ni(CN)4]2-, CN- is a strong field ligand due to which pairing leads to no unpaired electron in
3d- orbital/ Or structural representation
b) (i)
(ii)
33. Write IUPAC name of the complex [Co(en)2(H2O)(CN)]2+. 2019
Answer:
Aquacyanidobis(ethylenediamine)cobalt(III) ion
OR
Using IUPAC norms, write the formula of Ammonium tetrafluoridocobaltate(II).
Answer:
(NH4)2 [CoF4]
34. (a) Give one chemical test as an evidence to show that [Co(NH3)5Cl]SO4 and [Co(NH3)5(SO4)]Cl are 2019
ionisation isomers.
(b) [NiCl4]2– is paramagnetic while [Ni(CO)4] is diamagnetic though both are tetrahedral. Why? (Atomic
no. of Ni = 28)
(c) Write the electronic configuration of Fe(III) on the basis of crystal field theory when it forms an
octahedral complex in the presence of
(i) strong field ligand, and (ii) weak field ligand. (Atomic no. of Fe = 26)
Answer:
a) On addition of silver nitrate, [Co(NH3)5(SO4)] Cl will form white precipitate of AgCl while other does
not.(Or any other correct chemical test).
b)In [Ni(CO)4], Ni is in zero oxidation state whereas [NiCl4]2- ,it is in +2 oxidation state. In the presence of
CO ligand the unpaired d electrons of nickel pair up but Cl- being a weak ligand is unable to pair up the
unpaired electrons.
c)i) Strong field ligand ---
ii) Weak field ligand ----
35. Write IUPAC name of the complex K3[Cr(C2O4)3] 2019
Answer:
Potassium trioxalatochromate(III)
OR
Using IUPAC norms write the formula of Hexaamminecobalt(III) sulphate.
Answer:
[Co(NH3)6]2 (SO4)3
36. Write IUPAC name of the complex [Co(en)2Cl2]+. 2019
Answer:
Dichloridobis(ethylenediamine)cobalt(III) ion.
OR
Using IUPAC norms, write the formula of Sodium tetrachloridonickelate(II).
Answer:
Na2[NiCl4]
37. When a coordination compound CrCl3 . 6H2O is mixed with AgNO3, two moles of AgCl are precipitated 2019
per mole of the compound. What is the structural formula of the coordination compound?
Answer:
[Cr(H2O)5Cl]Cl2. H2O / [Cr(H2O)5Cl]Cl2
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QUESTION BANK
UNIT 5 COORDINATION COMPOUNDS
CLASS-12 (CBSE)
OR
What is the difference between a complex and a double salt?
Answer:
Double salt dissociates in simple ions completely when dissolved in water while Complex salt does not.
38. Write the hybridization and magnetic character of the following complexes : 2019
(i) [Fe(H2O)6]2+ (ii) [Ni(CN)4]2- [Atomic number : Fe = 26, Ni = 28]
Answer:
(i) sp3d2, paramagnetic (ii) dsp2, diamagnetic
39. What type of isomerism is shown by complex [Co(NH3)5Cl]SO4 ? 2019
Answer:
Ionization isomerism
OR
Arrange the following in increasing order of crystal field splitting energy :
[Cr(CN)6]3–, [Cr(NH3)6]3+, [CrCl6]3–
Answer:
[Cr(Cl)6]3- < [Cr(NH3)6]3+ < [Cr(CN)6]3-
40. Using valence bond theory, predict the hybridization and magnetic character of the following : 2019
(a) [Co(NH3)6]3+ (b) [Ni(CO)4]
[At. no. : Co = 27, Ni = 28]
Answer:
a) d2sp3, diamagnetic
b) sp3, diamagnetic
41. Using valence bond theory, predict the hybridization and magnetic character of the following : 2019
(a) [CoF6]3– (b) [Ni(CN)4]2– [At. no. : Co = 27, Ni = 28]
Answer:
a) sp3d2, paramagnetic b) dsp2, diamagnetic
42. Using valence bond theory, predict the hybridization and magnetic character of the following : 2019
(a) [NiCl4]2– (b) [Co(C2O4)3]3– [At. no. : Co = 27, Ni = 28]
Answer:
a) sp3, paramagnetic b) d2sp3, diamagnetic
43. Write the coordination number and oxidation state of Platinum in the complex [Pt(en)2Cl2]. 2018
Answer:
Coordination Number = 6 , Oxidation State = +2
44. (a) Write the formula of the following coordination compound : 2018
Iron(III) hexacyanoferrate(II)
(b) What type of isomerism is exhibited by the complex [Co(NH3)5Cl]SO4 ?
(c) Write the hybridisation and number of unpaired electrons in the complex [CoF6]3–. (Atomic No. of Co
= 27)
Answer:
(a) Fe4[Fe(CN)6]3
(b) Ionisation isomerism
(c) sp3d2, 4
45. Using IUPAC norms write the formulae for the following : 2017
(a) Sodium dicyanidoaurate(I) (b) Tetraamminechloridonitrito-N-platinum(IV) sulphate
Answer:
(i) Na[Au(CN)2] (ii) [Pt(NH3)4Cl(NO2)]SO4
46. (a) What type of isomerism is shown by the complex [Co(NH3)5 (SCN)]2+ ? 2017
(b) Why is [NiCl4]2- paramagnetic while [Ni(CN)4]2-is diamagnetic?
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QUESTION BANK
UNIT 5 COORDINATION COMPOUNDS
CLASS-12 (CBSE)
(Atomic number of Ni = 28)
(c) Why are low spin tetrahedral complexes rarely observed?
Answer:
(a) Linkage isomerism
(b) In [NiCl4]2- ,due to the presence of Cl- , a weak field ligand no pairing occurs whereas in [Ni(CN)4]2- ,
CN- is a strong field ligand and pairing takes place / diagrammatic
representation
(c) Because of very low CFSE which is not able to pair up the electrons.
47. Using IUPAC norms write the formulae for the following : 2017
(a) Tris(ethane-1,2-diamine)chromium(III) chloride
(b) Potassium tetrahydroxozincate(II)
Answer:
(i) [Cr(en)3]Cl3
(ii) K2[Zn(OH)4]
48. Using IUPAC norms write the formulae for the following : 2017
(a) Potassium trioxalatoaluminate(III) (b) Dichloridobis(ethane-1,2-diamine)cobalt(III)
Answer:
a. K3[Al(C2O4)3]
b. [CoCl2(en)2]+
49. (i) What type of isomerism is shown by the complex [Co(NH3)6] [Cr(CN)6] ? 2017
(ii) Why a solution of [Ni(H2O)6]2+ is green while a solution of [Ni(CN)4]2– is colourless ? (At. no. of Ni =
28)
(iii) Write the IUPAC name of the following complex: [Co(NH3)5(CO3)]Cl.
Answer:
(i) Coordination isomerism
(ii) Unpaired electrons in [Ni(H2O)6]2+ / d-d transition
(iii) Pentaamminecarbonatocobalt(III) chloride
50. (i) What type of isomerism is shown by the complex [Co(en)3]Cl3 ? 2017
(ii) Write the hybridisation and magnetic character of [Co(C2O4)3]3–. (At. no. of Co = 27)
(iii) Write IUPAC name of the following Complex [Cr(NH3)3Cl3]
Answer:
(i)Optical isomerism
(ii)d2sp3, diamagnetic
(iii)Triamminetrichloridochromium(III)
51. (a) Write the IUPAC name of the isomer of the following complex : [Pt(NH3)2Cl2] 2017
(b) Write the formula for the following : Tetraammineaquachloridocobalt(III) nitrate
Answer:
(a) cis/ trans-diamminedichloridoplatinum(II)
(b) [Co(NH3)4(H2O)Cl] (NO3)2
52. (a) Define crystal field splitting energy. On the basis of crystal field theory, write the electronic 2017
configuration for d4 ion if Δo< P.
(b) [Ni(CN)4]2– is colourless whereas [Ni(H2O)6]2+ is green. Why? (At. no. of Ni = 28)
Answer:
(a) It is the magnitude of difference in energy between the two sets of d orbital i.e. t 2g and eg.
(b) In [Ni(H2O)6]2+, Ni+2(3d8) has two unpaired electrons which do not pair up in the presence of weak
field ligand H2O.
53. (a) Write the IUPAC name of the following complex : [Co(NH3)4Cl(NO2)]Cl 2017
(b) Write the formula for the following : Dichloridobis(ethane-1,2-diamine)cobalt(III) chloride
Answer:
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QUESTION BANK
UNIT 5 COORDINATION COMPOUNDS
CLASS-12 (CBSE)
(a) tetraamminechloridonitrito-N-cobalt(III) chloride
(b) [CoCl2(en)2] Cl
54. Define crystal field splitting energy. On the basis of crystal field theory, write the electronic configuration 2017
for d4 ion if Δo > P.
Answer:
It is the magnitude of difference in energy between the two sets of d orbital i.e. t2g and eg
55. (a) Write the IUPAC name of the isomer of the following complex : [Co(NH3)5Cl]SO4 2017
(b) Write the formula for the following : Diamminechloridonitrito-N-platinum(II)
Answer:
(a) Pentaamminesulphatocobalt(III) chloride
(b) [Pt(NH3)2Cl(NO2)]
56. When a coordination compound 𝐂𝐨𝐂𝐥𝟑. 𝟔𝐍𝐇𝟑 is mixed with 𝐀𝐠𝐍𝐎𝟑, 3 moles of AgCl are precipitated per 2016
mole of the compound. Write
(i) Structural formula of the complex (ii) IUPAC name of the complex.
Answer:
(i) [Co(NH3)6]Cl3
(ii) Hexaamminecobalt(III) chloride
57. (a) For the complex, [Fe(H2O)6]3+ write the hybridization, magnetic character and spin of the complex. 2016
(At. Number: Fe = 26)
(b) Draw one of the geometrical isomers of the complex [Pt(en)2Cl2]2+which is optically inactive.
Answer:
(a) sp3d2 , paramagnetic and high spin
(b)
58. When a co-ordination compound 𝑪𝒓𝑪𝒍𝟑. 𝟔𝑯𝟐𝑶 is mixed with 𝑨𝒈𝑵O𝟑, 2 moles of AgCl are precipitated 2016
per mole of the compound. Write.
(i) Structural formula of the complex. (ii) IUPAC name of the complex.
Answer:
(i) [Co(H2O)5Cl] Cl2.H2O
(ii) Pentaaquachloridocobalt(III) chloride
59. For the complex [Fe(CN)6]3−, write the hybridization type, magnetic character and spin nature of the 2016
complex. (At. number: Fe = 26).
Answer:
d2sp3, paramagnetic and low spin
60. (i) Write down the IUPAC name of the following complex: [𝑪𝒐(𝑵𝑯𝟑)𝟓𝑪𝒍]𝟐+ 2015
(ii) Write the formula for the following complex: Potassium tetrachloridonickelate(II).
Answer:
(i) Pentaamminechloridocobalt(III) ion
(ii) K2 [NiCl4]
61. (i) What type of isomerism is shown by the complex[𝑪𝒓(𝑯𝟐𝑶)𝟔]𝑪𝒍𝟑? 2015
(ii) On the basis of crystal field theory, write the electronic configuration for 𝒅𝟒 ion if 𝚫𝒐>𝑷.
(iii) Write the hybridization and shape of [𝑪𝒐𝑭𝟔]−. (Atomic no. of Co = 27)
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QUESTION BANK
UNIT 5 COORDINATION COMPOUNDS
CLASS-12 (CBSE)
Answer:
(i) Hydrate isomerism
(ii)
(iii) ) sp3d2 , octahedral
62. (i) Write down the IUPAC name of the following complex: 2015
[𝐂𝐫(𝐍𝐇𝟑)𝟐𝐂𝐥𝟐(𝐞𝐧)]𝐂𝐥 (𝐞𝐧 = 𝐞𝐭𝐡𝐲𝐥𝐞𝐧𝐞𝐝𝐢𝐚𝐦𝐢𝐧𝐞)]
(ii) Write the formula for the following complex: Pentaamminenitrito-o-cobalt(III).
Answer:
(i) Diamminedichlorido(ethylenediamine)chromium(III) chloride
(ii) [Co(NH3)5(ONO)]2+
63. (i) Draw the geometrical isomers of complex [Pt(NH3)2Cl2] 2015
(ii) On the basis of crystal field theory, write the electronic configuration for 𝒅𝟒 ion if Δ𝐨< 𝐏.
(iii) Write the hybridization and magnetic behavior of the complex [Ni(𝑪𝑶)4]. (At. no. of Ni = 28).
Answer:
(i)
(ii)
(iii) sp3 , diamagnetic
64. (i) Write the IUPAC name of the complex [Cr(NH3)4Cl2] Cl. 2014
(ii) What type of isomerism is exhibited by the complex [Co(en)3)]3+?
(iii) Why is [𝑵𝒊C𝒍𝟒]2−paramagnetic [𝑵𝒊(𝑪𝑶)𝟒] is a diamagnetic?
(𝑨𝒕. 𝑵𝒐𝒔. ∶ 𝑪𝒓 = 𝟐𝟒, 𝑪𝒐 = 𝟐𝟕, 𝑵𝒊 = 𝟐𝟖)
65. Which of the following is more stable complex and why? [𝑪𝒐(𝑵𝑯𝟑)𝟔]𝟑+ 𝐚𝐧𝐝 [𝑪𝒐(𝒆𝒏)𝟑]𝟑+ 2014
66. Write the IUPAC name of the complex [Cr(NH3)4Cl2]+. What type of isomerism does it exhibit? 2014
67. Write the IUPAC names of the following coordination compounds: 2013
(i) [𝐂𝐫(𝐍𝐇𝟑)𝟑𝐂𝐥𝟑] (ii) 𝐊𝟑[𝐅𝐞(𝐂𝐍)𝟔] (iii) [𝐂𝐨𝐁𝐫𝟐(𝐞n)𝟐]+, (𝐞𝐧 = 𝐞𝐭𝐡𝐲𝐥𝐞𝐧𝐞𝐝𝐢𝐚𝐦𝐢𝐧𝐞)
68. For the complex [𝑵𝒊𝑪𝒍𝟒]2−, write . 2013
(i) the IUPAC name.
(ii) the hybridization type.
(iii) the shape of the complex. (Atomic no. of Ni = 28)
69. Name the following coordination entities and draw the structures of their stereoisomers: 2012
(i) [Co (𝐞𝐧)𝟐𝐂𝐥𝟐]+(𝐞𝐧 = 𝐞𝐭𝐡𝐚𝐧e−𝟏, 𝟐−𝐝𝐢𝐚𝐦𝐢𝐧𝐞)
(ii)[𝐂𝐫(𝐂𝟐𝐎𝟒)𝟑]𝟑−
(iii) [𝐂𝐨(𝐍𝐇𝟑)𝟑𝐂𝐥𝟑]
(Atomic numbers Cr=24, Co=27)
70. Give the formula of each of the following coordination entities: 2012
(i) 𝑪𝑶𝟑2- ion is bound to one C𝒍−, one 𝑵𝑯𝟑 molecules and two bidentate enthylenediamine (en) molecules.
(ii) 𝑵𝒊𝟐+ ion is bound to two water molecules and two oxalate ions.
Write the name and magnetic behavior of each of the above coordination entities.
(At. Nos. Co=27, Ni =28)
71. Explain the following terms giving a suitable example in each case: 2011
(i) Ambident ligand
(ii) Denticity of a ligand
(iii) Crystal field splitting in an octahedral field.
72. Write the name, stereochemistry and magnetic behavior of the following” 2011
(𝐀𝐭. 𝐧𝐨𝐬. 𝐌𝐧 = 𝟐𝟓, 𝐂𝐎 = 𝟐𝟕, 𝐍𝐢 = 𝟐𝟖)
(i) 𝐊𝟒[𝐌𝐧(𝐂𝐍)𝟔]
(ii) [𝑪𝒐(𝑵𝑯𝟑)𝟓𝑪𝒍]𝑪𝒍𝟐
73. (a) What is meant by unidentate, bidentate and ambidentate ligands? Give two examples for each. 2011
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QUESTION BANK
UNIT 5 COORDINATION COMPOUNDS
CLASS-12 (CBSE)
(b) Calculate the overall complex dissociation equilibrium constant for the [Cu(𝑵𝑯𝟑)4]2+ ion, given that 𝜷𝟒 2007
for this complex is 𝟐. 𝟏×𝟏𝟎𝟏𝟑.
74. Give an example of linkage isomerism? 2010
75. Name the following coordination compounds according to IUPAC system of nomenclature: 2010
(i) [Co(𝐍𝐇𝟑)(𝐇𝟐𝐎)𝐂𝐥]𝐂𝐥𝟐
(ii) [CrCl2(𝐞𝐧)2]𝐂𝐥, (𝐞𝐧 = 𝐞𝐭𝐡𝐚𝐧𝐞 − 𝟏, 𝟐 − 𝐝𝐢𝐚𝐦𝐢𝐧𝐞)
76. Giving a suitable example for each, explain the following: 2009
(i) Crystal field splitting
(ii) Linkage isomerism
(iii) Ambidentate ligand
77. Compare the following complexes with respect to structural shapes of units magnetic 2009
behavior and hybrid orbitals involved in units:
[𝑪𝒐(𝑵𝑯𝟑)𝟔]𝟑+, [𝑪𝒓(𝑵𝑯𝟑)𝟔]𝟑+, 𝑵𝒊(𝑪𝑶)𝟒 𝑨𝒕. 𝑵𝒐𝒔: 𝑪𝒐 = 𝟐𝟕, 𝑪𝒓 = 𝟐𝟒, 𝑵𝒊 = 𝟐𝟖
78. For the complex [𝑭𝒆(𝒆𝒏)𝟐C𝒍𝟐]𝑪𝒍, (en=ethylene diamine), identify 2009
(i) The oxidation number of iron,
(ii) The hybrid orbits and the shape of the complex,
(iii) The magnetic behavior of the complex.
(iv) The number of geometrical isomers,
(v) Whether there is an optical isomer also, and
(vi) name of the complex. (At. No. of Fe = 26)
79. (a) What is the basis of formation of the spectrohemical series? 2008
(b) Draw the structures of geometrical isomers of the following coordination complexes:
[𝑪o(𝑵𝑯𝟑)𝟑 𝑪𝒍𝟑] and [𝑪𝒐𝑪𝒍𝟐(𝒆𝒏)𝟐]+
(en = ethylenediamine and atomic number of Co is 27).
80. (a) What is a ligand? Give an example of a bidentate ligand. 2008
(b) Explain as to how the two complexes of nickel, [Ni(𝐂𝐍)𝟒]𝟐−and Ni(𝐂𝐎)𝟒 have different structures but
do not differ in their magnetic behavior. (Ni = 28)
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