Question

The sum of coordination number and oxidation number of the
metal M in the complex [M(en)₂(C₂O₄)]Cl (where en is
ethylenediamine) is: [2015 RS]
(a) 9 (b) 6
(c) 7 (d) 8

Answer 1

a) 9 is the sum of coordination number and oxidation number

Explanation:

let oxidation state of m be 'x'

hence,             x + 1(0) + 2(-2) = 1

therefore,        x = 3             .......(1)

Coming on to C.N.

Both en and C2O4 are didentate ligands

therefore C.N = 2(2) + 1(2)

                      = 6              ............(2)

adding eq (1) and (2) we get

6 + 3

= 9

C.N. stands for Coordination No