Question

The effective atomic number of $Co(CO{)}_4$ is 35 and hence is less stable. It attains stability by:

• A. Reduction of $Co$
• B. Dimerization
• C. Both (a) and (b)
• D. None of these

Answer 1

The correct option is C Both (a) and (b)

As on dimerisation, the EAN of each $Co$ metal becomes 36; EAN = 27 + 1 + 8 = 36.
Reduction of $Co$ means gain of one electron, so it becomes $35+1=36$.