The oxidation number of cobalt in K[Co(CO)4] is (i) +1 (ii) +3 (iii) -1 (iv) -3
We recognise that CO is a impartial ligand and K includes a fee of 1. Therefore, the complicated may be written as K [Co(CO)4] - . Therefore, the oxidation quantity of Co withinside the given complicated is -1. Hence, option (iii) is correct.
