question_answer 35)

Give example and suggest reasons for the following features of transition metal chemistry: (a) The lowest oxide of the transition metal is basic while the highest is acidic. (b) A transition metal exhibits higher oxidation states in oxides and fluorides. (c) The highest oxidation state is exhibited in oxoanions of a metal.

Answer:

(a) It may be noted that in the different oxides of the same element, the acidic strength increases with the increase in oxidation stateof the clement. MnO (Mn2+) is basic because the metal atom in low oxidation state can donate electrons while Mn2O7 (Mn7+) is acidic because the metal atom has highest oxidation state. (b)Both oxygen and fluorine being smaller in size and highly electronegative can oxidize the transitation metal. (c)This is also because of the high electro negativity of oxygen and its tendency to act as oxidising agent. For example, chromium exhibits oxidation state of (VI) in oxoanion [Cr(VI)O4]2– and manganese shows oxidation state of (VII) in oxoanion [Mn(VII)O4]–.