Question

Which isomer of $CrC{l}_3.6H_{2}O$ is dark green in colour and forms one mole of $AgCl$ with excess of $AgN{O}_3$ solution -

• A. $\left[Cr\right(H_{2}O{)}_6]C{l}_3$
• B. $\left[Cr\right(H_{2}O{)}_{5}Cl]C{l}_2.H_{2}O$
• C. $\left[Cr\right(H_{2}O{)}_{4}C{l}_2]Cl.2H_{2}O$
• D. $\left[Cr\right(H_{2}O{)}_{3}C{l}_3].3H_{2}O$

Answer 1

The correct option is C $\left[Cr\right(H_{2}O{)}_{4}C{l}_2]Cl.2H_{2}O$

Since the complex $\left[Cr\right(H_{2}O{)}_{4}C{l}_2]Cl.2H_{2}O$ give 1 - mol
$C{l}^{-}$ ion in aqueous solution, thus it givesone mole of $AgCl$ with excess $AgN{O}_3$ solution.

Similarly, $\left[Cr\right(H_{2}O{)}_6]C{l}_3$ will give 3 moles of $AgCl$ with excess $AgN{O}_3$ and $\left[Cr\right(H_{2}O{)}_{5}Cl]C{l}_2.H_{2}O$ will give 2 moles of $AgCl$ with excess $AgN{O}_3$. $\left[Cr\right(H_{2}O{)}_{3}C{l}_3].3H_{2}O$ this will not form $AgCl$ since it has no $C{l}^{-}$ ion outside the coordination sphere.