Question

When a co-ordination compound NiCl₂·6H₂O mixed with AgNO₃, 2 moles of AgCl are precipitated per mole of the compound. Write

Werner's coordination theory in 1893 was the first attempt to explain the bonding in coordination complexes. It must be remembered that this theory was put forward before the electron had been discovered by J.J. Thomson in 1897, and before the electronic theory of valency. Werner did not have any of the modern instrumental techniques and all his studies were made using simple experimental techniques. Werner was able to explain the nature of bonding in complexes and he concluded that in complexes, the metal shows two different sorts of valency : primary and secondary. Primary valences are normally ionisable whereas secondary valences are non ionisable. Answer the following questions :

The coordination number of Co in [Co(en)₃]³⁺ is :

On adding AgNO₃ solution to 1 mole of complex NiCl₂ . 4NH₃, two moles of AgCl are formed. The secondary valency of Ni in the complex will be :