Question

Probable complex (assume that coordination number of chromium is six) can be :

• A. $\left[Cr\right(N{H}_3{)}_6]C{l}_3$
• B. $\left[Cr\right(N{H}_3{)}_{5}Cl]C{l}_2$
• C. $\left[Cr\right(N{H}_3\left)C{l}_2\right]Cl$
• D. $\left[CrC{l}_3\right].6N{H}_3$

Answer 1

The correct option is A $\left[Cr\right(N{H}_3{)}_6]C{l}_3$

The number of moles of $HCl=0.040\times 1.5=0.06$ moles.
The number of moles of the chromium complex $\left(A\right)=\frac{0.06}{x}$
Mass of complex $A=2.635$ g.
Molecular mass of complex $A=\frac{2.635}{\frac{0.06}{x}}$
When $x=6$, the molar mass will be $\frac{2.635}{\frac{0.06}{6}}=263.5$ g.
Molecular mass of the formula $\left[Cr\right(N{H}_3{)}_6]C{l}_3$ is $267.5$ g/mol.
Thus, the most probable molecular formula of the complex is $\left[Cr\right(N{H}_3{)}_6]C{l}_3$.