D and F BLOCK ELEMENTS

D and F BLOCK ELEMENTS

1. Through copper, silver and gold have completely filed sets of d-orbitals yet they are considered as transition metals. Why?
2. Why does Mn(II) show maximum paramagnetic character amongst the bivalent ions of the first transition series?
3. Why Zn²⁺ salts are white while Ni²⁺ salts are blue?
4. Why Zn2+ salts are white while Cu²⁺ salts are blue?
5. [Ti(H2O)₆]³⁺ is colored while [Sc(H2O)₆]³⁺ is colorless. Explain.
6. Giving reasons indicate which one of the following would be colored?
7. Zinc, cadmium and mercury are generally not considered as transition metals. Give reasons.
8. K₂PtCl₆ is a well known compound whereas corresponding Ni compounds is not known. State a reason for it.
9. Most of the transition metals do not displace hydrogen from dilute acids. Why?
10. Why have the transition elements high enthalpy of hydration?
11. Why is copper sulphate pentahydrate colored?
12. A substance is found to have a magnetic momen of 3.9 B.M. How many unpaired electrons does it contain?
13. Why do transition elements show variable oxidation states
14. Why are the ionization energies of 5d elements greater than 3d elements?
15. The melting and boiling points of Zn, Cd and Hg are low. Why?
16. Lime stone is used in the manufacture of pig iron from haematite. Why?
17. Give one important difference between Pig iron (cast iron), wrought iron and steel?
18.  What is Thomas slag? What is its use?
19. What substance is added to adjust carbon content in steel?
20. What do you understand by quenching, tempering and annealing of steel?
21. What is the composition of ‘matte’?
22. What is ‘Bessemerisation’? What reactions take place during ‘Bessemerisation’?
23. What is ‘Horn silver’? What is its formula?
24. Why a green layer appears on the surface of copper vessel after some time?
25. How is granulated zinc obtained?
26. Why does zinc become dull in moist air?
27. How are H₂O molecules bonded in CuSO₄.5H₂O?
28. What happens when H₂O molecules are linked by co-ordinate bonds to the central Cu²⁺ ion while the fifth is attached to SO₄^2- ion by hydrogen bonding?
29. What reaction will take place if a silver coin is put in dilute HNO₃?
30. A white ppt. of Ag₂S₂O₃ is obtained which turns yellow, brown and finally black on keeping.
31. Why shining copper turnings turn black when placed in aqueous mercuric chloride solution?
32. What happens when mercuric chloride is treated with excess of KI solution?
33. What happens when NH3 is passed through Nessler’s reagent. Give the reaction involved.
34. Why is hydrochloric acid not used to acidify a permanganate in volumetric estimation of Fe²⁺ and C₂O₄^2- ?
35. Give