Arun Kumar Das Gupta , populerly know to his students as AKD sir, is a 1 st class M.Sc in inorganic chemistry from Calcutta university. He is also a 1 st class B.Ed from Calcutta university. He is teaching chemistry in secondary and senior secondary level for last 30 years. AKD sir is writer and editor of few books and articles.

Co-ordination Compounds |
November 9, 2017

UNIT – 9

CO-ORDINATION COMPOUNDS

1 Mark Questions

  1. Write the IUPAC name of the complex Na3[Cr(OH)2F4].
  2. Write the IUPAC name of [CO(en)2Cl(ONO)]+
  3. Which of these cannot act as ligand and why: NH3, H2O, CO, CH4. Give reason?
  4. NH3 is strong ligand NH4+ ion is not, why?
  5. Which of the two is more stable K4[Fe(CN)6] or K3[Fe(CN)6].

6.Why do tetrahedral complex not show geometrical isomerism?

  1. Why does the colour changes on heating [Ti(H2O)6]3+
  2. [Fe(H2O)6]3+ is strongly paramagnetic whereas [Fe(CN)6]3- is weakly paramagnetic. Explain.
  3. What happens when potassium ferrocyanide solution is added to a ferric salt solution?
  4. Write the oxidation state of Nickel in [Ni(CO)4].
  5. What is ambidentate ligand ? Give one example.
  6. Write the IUPAC name of [PtCl2(en)2(NO3)2].
  7. Write the name of a complex compound used in chemotherapy.
  8. What is a chelate ligand ? Give one example.

15.Name one homogeneous catalyst used in hydrogenation of alkenes.

  1. How many geometrical isomers are possible for the [Ni(NH3)4]+2 ?
  2. Write IUPAC name of [Co(C2O4)3]-3.
  3. Give an example of coordination isomerism.
  4. Name an ionization isomer of [Cr(H2O)5Br]SO4.
  5. Give the chemical formula of potassium hexacyano ferrate (II).
  6. Which of these cannot act as a ligand ? NH3, H2O, CO, NH4+
  7. Give one use of Ziegler Natta catalyst.
  8. Name the metal present in : (i) Chlorophyll (ii) Haemoglobin (iii) Vit. B-12 (iv) cis platin

25.The chemical formula of Wilkinson.s catalyst is :

  1. How many moles of AgCl will be precipitated when an excess of AgNO3 is added to a molar solution

of [CrCl(H2O)5]Cl2 ?

  1. Which type of ligands form chelates ?
  2. Arrange the following complexes in order of increasing electrical conductivity :

[CO(NH3)3Cl3], [Co(NH3)5Cl]Cl2, [Co(NH3)4]Cl3

 

 

2 / 3 Mark Questions

  1. A coordination compound has a formula (CoCl3. 4NH3). It does not liberate NH3 but precipitates chloride ion as AgCl. Give the IUPAC name of the complex and write its structural formula.
  1. How is stability of co-ordination compounds determined in aqueous solution? Select a complex formation reaction and write an expression for the stability constant of the complex. Mention the factors affecting stability of complexes.
  1. Why do tetrahedral complex not show geometrical isomerism?
  2. Write the correct formula for the following co-ordination compounds.

CrCl3 . 6H2O (Violet, with 3 Chloride ions/ Unit formula)

CrCl3 . 6H2O (Light green colour with 2 Chloride ions/ unit formula)

CrCl3 . 6H2O (Dark green colour, with 1 Chloride ion/ unit formula)

  1. Aqueous copper sulphate solution (blue in colour) gives:
  2. a green precipitate with aqueous potassium flouride
  3. a bright green solution with aqueous potassium chloride. Explain these experimental results.
  1. Identify complexes with different geometries depending upon the type of hybridization. (a) [Co (NH3)6]3+ (b) [CoF6]3-
  1. One mole of complex compound Co(NH3)5Cl3 gives 3 moles of ions on dissolution in water.  One mole of same complex reacts with 2 moles of AgCl(s). What is the structure of the complex and write its formula.
  1. When an aquous solution of Nickel (II) chloride is mixed with ethane-1,2 diamine(en) in the molar ratios en : Ni=1:1, 2:1 and 3:1, the green coloured solution finally turns violet. Explain the chemical reactions based on the data provided.
  2. A coordination compound has a formula (CoCl3. 4NH3). It does not liberate NH3 but precipitates chloride ion as AgCl. Give the IUPAC name of the complex and write its structural formula.
  3. Write the correct formula for the following co-ordination compounds.  CrCl3 . 6H2O (Violet, with 3 Chloride ions/ Unit formula)

CrCl3 . 6H2O (Light green colour with 2 Chloride ions/ unit formula)

 

  1. Give the electronic configuration of the d-orbitals of Ti in [Ti (H2O) 6]3+ ion in an octahedral crystal field.
  2. Co(II) is stable in aqueous solution but in the presence of strong ligands and air,  it can get oxidized to Co(III). (Atomic Number of cobalt is 27). Explain.
  3. Give a chemical test to distinguish between [Co(NH3)5Br]SO4 and [Co(NH3)5Br]SO4Br. Name the type of isomerism exhibited by these compounds.
  4. What is the coordination entity formed when excess of aqueous KCN is added to an aqueous solution of copper sulphate? Why is that no precipitate of copper sulphate is obtained when H2S (g) is passed through this solution?

 

  1. Calculate the magnetic moments of the following complexes :

(i) [Fe(CN)6] -4 (ii) [FeF6] -3

16.. Mention the main postulates of Werner theory.

  1. Draw the structure of :

(i) [Ni(CO)4] (ii) [Fe(H2O)6] +3

  1. How does EDTA help as a cure for lead poisoning ?
  2. Define homoleptic and heteroleptic complexes.
  3. [NiCl4]2 is paramagnetic while [Ni(CO)4] is diamagnetic though both are tetrahedral. Why ?
  4. The oxidation number of cobalt in the complex : (i) K[Co(CO)4] (ii) [Co(C2O4)3]3
  5. What are t2g and eg orbitals ?
  6. What is spectrochemical series ?
  7. CuSO4 is colourless while CuSO4.5H2O is coloured. Why ?
  8. What is the difference between inner and outer orbital complexes ?
  9. How is stability of coordination compound determined in aqueous solution ?
  10. In a complex ion [Co(NH3)5NO2]Cl2,

(i) Identify the ligand.

(ii) Oxidation number of metal ion.

  1. Explain how the nature of ligand affects the stability of complex ion.
  2. What is meant by denticity of a ligand ? Find out denticity of : (i) C2O4 –2 (ii) EDTA -4
  3. Why does a tetrahedral complex of the type [MA2B2] not show geometrical isomerism ?
  4. Why does a tetrahedral complex of the type [MA2B2] not show geometrical isomerism ?
  5. The molar conductivity of the complex CoCl3.4NH3.2H2O is found to be same as that of 3 : 1 electrolyte. What is the structural formula. Name and number of geometrical isomer of the complex.
  6. [Ti(H2O)6]3+ is coloured while [Sc(H2O)6]3+ is colourless. Why ?
  7. Describe with an example of each, the role of coordination compounds in :

(i) Biological system

(ii) Analytical chemistry

(iii)Medicinal chemistry

  1. Write the type of isomerism exhibited by the following complexes :

(i) [Co(NH3)5Cl]SO4

(ii) [Co(en)3]+3

(iii) [Co(NH3)6][Cr(CN)6]

  1. Explain the following :

(i) CO is stronger ligand than NH3.

(ii) Low spin octahedral complexes of nickel are not known.

(iii)Aqueous solution of [Ti(H2O)6]+3 is coloured.

  1. Write all the geometrical isomers of [Pt(NH3)(Br)(Cl)(Py)] and how many of these will exhibit optical isomerism ? Here, Py = Pyridine.

(5 Marks)

  1.  A metal ion M n+ having d4 valence electronic configuration combines with three didentate ligands to form a complex compound. Assuming Δo > p :

(i) Draw the diagram showing d-orbital splitting during this complex

formation.

(ii) What type of hybridisation will M n+ have ?

(iii) Name the type of isomerism exhibited by this complex.

(iv) Write the electronic configuration of metal M n+.

  1.  (i) Discuss the nature of bonding in metal carbonyls.

(ii) Draw figure to show the splitting of d-orbitals in an octahedral crystal field and write electronic configuration of Mn 3+ ion when :

(a) p > Δo

(b) Δo > p

  1.  (i) [Fe(CN)6] 4 and [Fe(H2O)6] 2+ are of different colours in dilute solution. Why ?

(ii) A complex is prepared by mixing CoCl3 and NH3 in the molar ratio of 1 4.  0.1M solution of this complex was found to be freeze at . 0.372º C. What is the formula of the complex ? Kf = 1.86 ºC/M

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