The equivalents of ethylene diamine required to replace the neutral ligands from the coordination sphere of…

1. trans- ${\mathrm{CoCl}}_3.4{\mathrm{NH}}_3$
or

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

As we know that ethylene diamine is a bidentate ligand and ammonia is a mono dentate ligand.

It means overall two ethylene diamine is required to replace the all neutral ligands (four ammonia) from the coordination sphere of this complex.