(a) Complete the following equations: (i) Cr_2O_(7)^(2-) + 2OH^(-) to (ii)MnO_(4)^(-) + 4H^(+) + 3e^(-) (b) Account for the following: (i) Zn is not considered as a transitionelement. (ii) Transition metals form a large number of complexes. (iii) The E^(0) value for the Mn^(3+)//Mn^(2+) couple is much more positive than that for Cr^(3+)//Cr^(2+) couple.

(a) Complete the following equations: (i) Cr_2O_(7)^(2-) + 2OH^(-) to

1.	(a) Complete the following equations: (i) Cr_2O_(7)^(2-) + 2OH^(-) to (ii)MnO_(4)^(-) + 4H^(+) + 3e^(-) (b) Account for the following: (i) Zn is not considered as a transitionelement. (ii) Transition metals form a large number of complexes. (iii) The E^(0) value for the Mn^(3+)//Mn^(2+) couple is much more positive than that for Cr^(3+)//Cr^(2+) couple.
Answer» Solution :(a)(i) `Cr_2O_(7)^(2-) + 2OH^(-) to CrO_(4)^(2-) + H_2O` (ii) `MnO_(4)^(-) + 4H^(+) + 3e^(-) to MnO_(2) + 2H_2O` (b) (i) `Zn//Zn^(2+)` has fully FILLED d-orbitals. (ii) This is due to smaller IONIC sizes/higher ionic charge and availability of d-orbitals. (iii) Because `MN^(2+)` is more stable `(3d^5)` than `Mn^(3+) (3d^4)`.`Cr^(+3)` is more stable due to `t_(2g)^(3)//d^(3)`, configuration.