posted by Ranger .
what accounts for the colour change from green to blue in the reaction below
[Ni(H2O)6]Cl2 + 6NH3 --> [Ni(NH3)6]Cl2 + 6H2O
its because of addition of ammonia and dehydrogenation occurs
Anjana may have meant dehydration and not dehydrogenation. Primarily it's because of the change from water as a complexing agent to ammonia as a complexing agent. Ammonia is a stronger field splitting agent (eg and t2g) then water and shows a larger energy difference between the two levels.