Question

Consider the complex $\left[Co\right(N{H}_3{)}_{5}Cl]Cl{O}_4$. The co-ordination and oxidation number (magnitude only) on the metal are, respectively :

• A. 6 and 2
• B. 6 and 4
• C. 4 and 3
• D. 4 and 2

Answer 1

The correct option is A 6 and 2

There are 5 $N{H}_3$ molecules and one $C{l}^{-}$ ion in the coordination complex. So, the coordination number is 6. The oxidation number of cobalt in the complex is +2. As, the overall charge on the complex ion is +1 and Cl has -1 charge. So, Co should have +2 charge to balance the overall charge.