The equivalents of ethylene diamine required to replace the neutral ligands from the coordination sphere of the trans-complex of $$CoCl_3 \cdot 4NH_3$$ is ________. (Round off to the Nearest Integer).

The trans-complex of $$CoCl_3 \cdot 4NH_3$$ is a Werner complex. According to Werner's theory, cobalt(III) has a coordination number of 6.

The complex can be written as $$[Co(NH_3)_4Cl_2]Cl$$, where 4 $$NH_3$$ molecules and 2 $$Cl^-$$ ions are in the coordination sphere, and 1 $$Cl^-$$ is the counter ion. In the trans-isomer, the two chloride ligands are opposite to each other.

The neutral ligands in the coordination sphere are the 4 $$NH_3$$ molecules. We need to replace these with ethylene diamine (en), which is a bidentate ligand. Each ethylene diamine molecule can replace two $$NH_3$$ molecules since it occupies two coordination sites.

Therefore, to replace 4 $$NH_3$$ molecules, we need $$\frac{4}{2} = 2$$ equivalents of ethylene diamine.

The answer is $$\mathbf{2}$$.