The conductivity of a solution of complex with formula CoCl 3 NH 3 4 corresponds to 1 : 1 electrolyte, then…

Primary valencies are ionizable. If the complex ion exhibits positive charge, then primary valence corresponds to the number of charges present and is balanced by the same number of negative ions. Hence, primary valency can also be defined by the number of anions neutralizing the charge on the complex. 

$\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_4{\mathrm{Cl}}_2\right]\mathrm{Cl}$

The above complex can be represented as ${\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_4{\mathrm{Cl}}_2\right]}^{+}{\mathrm{Cl}}^{-}$. Hence, the primary valency of above complex is 3.