(a) Why do transition elements show catalytic properties? (b) Calculate equivalent weight of `KMnO_4` in neutral medium. ( c) What is the cause of lanthanoid contraction?

The equivalent weight of KMnO_4 in a redox reaction in a neutral medium is .

(a) Why do transition elements show variable oxidation states? (i) Name the element showing maximum number of oxidation states among the first series of transition metals from Sc (Z = 21) to Zn (Z = 30). (ii) Name the element which shows only + 3 oxidation state. (b) What is lanthanoid contraction? Name an important alloy which contains some of the lanthanoid metals.

(a) Why do transition metals act as good catalysts? (b) Why do transition metals form alloys ? (c) What are coinage metals ?

(i) What are transition elements ? (ii) Why do transition elements show variable oxidation states ?

(a) Why do the transition elements exhibit higher enthalpies of atomization? (b) Draw the structure of Cr_2O_7^(2-) ion. (c) Why is hydrochloric acid not used in potassium permanganate titrations?

(a) Why do transition metals and their compounds are found to be good catalysts? (b) The 5d series of transition metals have more frequent metal-metal bonding in their compounds than do the 3d and 4d metals. Explain. (c ) Why do transition metals form complexes? (d) Explain why Cu^+ ion is not stable in aqueous solution. (e ) Why is europium (II) more stable than cerium (II)?

(a). Why second asnd third transition series elements show similar size? (b). Why electronic configuration of lanthanoids not known with certainty? (c). The electronic configuration of actinide elements are not known with certainty. Explain. (d). Why there is similarties (horizontal and vertical) in successive members of the transition series?

The equivalent weight of KMnO_(4) in (a) neutral medium, (b) acidic medium and (c ) alkaline medium is M//.. ( where M is mol.wt. of KMnO_(4) )