HOTS (coordination compounds)

1. A cationic complexes have two isomers A & B. Each has one Co+3, five NH3, one Br- and one SO4

2-.Agives a white precipitate with Bacl2 solution while B gives a yellow precipitate with AgNO3 solution.

(a) What are the possible structures of the complexes A&B?(b) Will the two complexes have same colour?

2. A student prepared three co-ordination complexes containing containing chromium having the following characteristics: Formula colour Cl- ions present in solution per formula unit(A) CrCl3.6H2O violet 3(B) CrCl3.6H2O Light green 2(C) CrCl3.6H2O Dark green 1(a) Write the structures of the three complexes.(b) Give IUPAC name of the complex

3. A, B and C are three complexes of chromium with the empirical formula H12O6Cl3Cr.All the three complexes have Cl and H2O molecules as the ligands. Complex A does not react with Conc.H2SO4. Complexes B and C lose 6.75% and 13.5% of their original weight respectively on heating with Conc. H2SO4. Identify A, B and C.

4. (a) Classify the following into cationic, anionic and neutral complexes:(i) [Cr(NH3)4 Cl2] Cl (ii) K4[Fe(CN)6] (iii) [Co( NH3)5Cl3](b)Write IUPAC name of the complex [Ni (dmg) 2](c) Why does complex [Al (NH3)6]3+ not exist in aqueous solution?

5. Describe simple test that will allow you to distinguish between the compounds:[Co (NH3)5Br]SO4 and [Co (NH3)5SO4] Br.

6. One mole of aqueous solution of the complex CoCl3 .5H2O when treated with excess of AgNO3 solution gave one mole of white ppt of AgCl.What is the complex?

7. A coordination compound has the formula CoCl3.4NH3.It does not liberate ammonia but precipitates chloride ions as silver chloride. Give the structural formula of the complex and write its IUPAC name.

8. Write the IUPAC name & hybridisation of K [Co (en) Cl4].

9. 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 freeze at -0.3720C. What is the formula of the complex? Given that molal depression constant (Kf) for water=1.86oC/m.

10. A metal complex having the composition Cr (NH3)4 Cl2Br has been isolated in two forms A&B. The form A reacts with AgNO3 solution to give a white ppt readily soluble in dilute aqueous solution to give a white ppt readily soluble in

dilute aqueous ammonia where as B gives a pale yellow ppt soluble in Conc. Ammonia solution. Write the formula of A&B.

11. Write the geometrical isomers of [Pt (NH3) (Cl) (py) Br] and show how many of these will exhibit optical isomerism.

12. On the basis of valence bond theory explain geometry, nature of hybridisation, magnetic property & optical isomerism of [Co (OX) 3] 3- and [CoF6}3-

13. Calculate the magnetic moment of the following complexes; (i) [Cr (NH3)6]3+ (ii) [CoF6]3- (iii) [Fe (CN)6]3-

14. A metal ion Mn+ having d4 valence electronic configuration combines with

three didentate ligands to form a complex compound. Assuming (i) Draw the diagram showing d orbital splitting during this complex formation.(ii) write the electronic configuration of the valence electrons of the metal Mn+ ion in terms of t2g and eg.(iii) What type of hybridization will Mn+ ion have?(iv) Name the type of isomerism exhibited by this complex.

15. Why does a tetrahedral complex of the type [MA2 B2] not show geometrical isomerism?

16. Aqueous copper sulphate solution (blue in colour) gives:(i) A green precipitate with aqueous potassium fluoride and(ii) a bright green solution with aqueous potassium chloride. Explain theseexperimental results.

17. What is the coordination entity formed when excess of aqueous KCN isadded to an aqueous solution of copper sulphate? Why is it that no precipitateof copper sulphide is obtained when H2S(g) is passed through this solution?

18. Amongst the following, the most stable complex is(i) [Fe (H2O) 6]3+ (ii) [Fe(NH3)6]3+ (iii) [Fe(C2O4)3]3– (iv) [FeCl6]3–

19. What will be the correct order for the wavelengths of absorption in theVisible region for the following:[Ni (NO2)6]4–, [Ni (NH3)6]2+, [Ni (H2O) 6]2+?

20. Write down the IUPAC name for each of the following complexes and indicate the oxidation state, electronic

configuration and coordination number. Also give stereochemistry and magnetic moment of the complex:(i) K [Cr (H2O)2(C2O4)2].3H2O (iii) CrCl3(py)3 (v) K4[Mn(CN)6](ii) [Co (NH3)5Cl] Cl2 (IV) Cs [FeCl4]