Werner's theory was the first successful theory, which explained the properties of complexes. According to Werner's theory the primary and secondary valence of `[Co(Cl_3(NH_3)_3]Cl_3` is :
| A. |
3 & 3 respectively |
| B. |
6 & 6 respectively |
| C. |
3 & 6 respectively |
 |
| D. |
6 & 3 respectively |
According to Werner's theory primary valence means oxidation state and secondary valance means coordination number. Let oxidation state of Co in `[CoCl_3 (NH_3 ) 3Cl_3` is x
x – 3 + 0 = + 3 x = 0
Primary valence = 3 Secondary valence = coordination numbers = 6