Ncert Exercises & Solutions

9.30 The oxidation number of cobalt in K[Co(CO)₄] is

(i) +1 (ii) +3 (iii) –1 (iv) –3

Step 1:

The CO is a neutral ligand K has +1 charge

Step 2:

Calculate the oxidation state of Co is as follows:

1 + x + (4×0) = 0
x = -1
Hence, option (iii) is correct and the oxidation state of Co is -1.