Question

$Co.{Cl}_3.5{NH}_3{H}_{2}O$ is a pink solid, the solution of this salt is also pink and formed $3$ mol of $AgCl$ with silver nitrate solution. On heating pink solid, it loses one water molecule and forms purple solid having same ratio of $Co:{NH}_3:Cl$ as that of pink solid. The purple solid when dissolved in water and treated with silver nitrate forms $1$ mol of $AgCl$. Draw the structures and name of the pink and purple solids.

Answer 1

The given pink solid is $\left[Co\right(N{H}_3{)}_5\left(H_{2}O\right)]C{l}_3$. The name of this complex is Pentaamineaquacobalt (III) Chloride. The purple solid is $\left[Co\right(N{H}_3{)}_5]C{l}_3$. The name of this complex is Pentaaminechlorocobalt (III) Chloride.Since the first complex, as given forms $3$ moles of $AgCl$ with $AgN{O}_3$ so it must have $3$ ionizable $C{l}^{-}$ ions and in second complex there are $2$ ionizable $C{l}^{-}$ ions.