The elevation of boiling point of 0.10 M aqueous CrCl₃.x NH₃ solution is two times that of 0.05 M aqueous CaCl₂ solution. The value of x is _____.

[assume 100% ionisation of the complex and CaCl₂, coordination number of Cr as 6, and that all NH₃ molecules are present inside the coordination sphere)

For 0.05 M CaCl₂, i = 3

Effective molarity of CaCl₂ = 0.05 × 3 = 0.15

effective molarity of complex  = 2 × effective molarity of CaCl₂ 

                                              = 2 × 0.15 = 0.3 M

So the complex is producing 3 ions on dissociation, which is possible only when, the value of x = 5.

$\left[Cr Cl {\left(N{H}_3\right)}_{ 5} \right] {\mathrm{Cl}}_2 \rightleftharpoons [\mathrm{Cr} \mathrm{Cl} {\left({\mathrm{NH}}_3\right)}_5 {]}^{2+}+2 {\mathrm{Cl}}^{-}$