Coordination number of Cr is three. A comlex ion of Cr with `C_(2)O_(4)^(2-)` end and superoxide ion, `O_(2)^(-)` has the fomula , `[Cr(CO_(2)O_(4))_(x)(en)_(y)(O_(2))_(z)]^(-)` The ratio `x:y:z` will be

Options

A. `1 : 1 : 1`
B. `1 : 1 : 2`
C. `1 : 2 : 2`
D. `2 : 1 : 1`

Answer

B

Explanation

x : y : z should be such that total charge =-1 (i.e. charge on the complex ion).
For (a)
total charge = + 3 + 1 (-2) + 1(0) + 1 (-1)=0
For (b),
Total charge = + 3 + 1 (-2) + 1 (0) + 2 (-1) =-1.