Q. One mole of $ CoC{{l}_{3}}.YN{{H}_{3}} $ complex compound on complete ionisation in water produces three moles of ions. If one chloride satisfies both primary and secondary valencies of cobalt ion, the value of Y is
EAMCETEAMCET 2010
Solution:
Since, the coordination number of Co is 6, there must be six ligands inside the coordination sphere. As one mole of complex give three moles of ions, two $ \text{C}{{\text{l}}^{-}} $ ions must present outside the sphere. Hence, the formula of the complex is $ [Co{{(N{{H}_{3}})}_{5}}Cl]C{{l}_{2}}.[Co{{(N{{H}_{3}})}_{5}}Cl]C{{l}_{2}} $ $ \xrightarrow{\text{Ionisation}}\underbrace{{{[Co{{(N{{H}_{3}})}_{5}}Cl]}^{2+}}+2\text{C}{{\text{l}}^{-}}}_{\text{3 }\,\text{ions}} $ In this complex one Cl atom satisfies both primary and secondary valencies as
Hence, the value of Y is 5.
