Question

When $AgN{O}_3$ solution is added in excess to $1M$ solution of $Co{Cl}_3.xN{H}_3$ one mole of $AgCl$ is formed? What is the value of $x$?

• A. $1$
• B. $4$
• C. $3$
• D. $2$

Answer 1

Answer: (B)

$4$

$CoC{l}_3.xN{H}_3+AgN{O}_3\to AgCl\left(1mole\right)$

This precipitation of 1 mol of AgCl by this reaction shows that there is only one $Cl$ outside the coordination sphere, which is not as a ligand ( as ligands are not ionisable).

Hence, the compound must be as follows: ( showing the coordination sphere) $\left[Co\right(N{H}_3{)}_{4}C{l}_2]Cl$, as this is the octahedral complex, where it is clear that there are only 2 Cl as ligand and other ligands are $N{H}_3$.

So, $6-2=4$ $N{H}_3$ ligands.

Hence, the answer is 4 and option is B.