Question

Which of the following has the highest molar conductivity?

• A. $\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_5\mathrm{Cl}\right]C{l}_2$
• B. $\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_6\right]C{l}_3$
• C. $\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_3{\mathrm{Cl}}_3\right]$
• D. $\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_4{\mathrm{Cl}}_2\right]Cl$

Answer 1

The correct option is B

$\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_6\right]C{l}_3$

The explanation for the correct answer

(B) $\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_6\right]C{l}_3$

1. The molar conductivity of the coordination complexes depends on the number of ions.
2. The more the number of ions more will be the molar conductivity.
3. $\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_6\right]C{l}_3$ has total four ions that are $3{\mathrm{Cl}}^{-}$ and ${\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_6\right]}^{3+}$.
4. Thus, $\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_6\right]C{l}_3$ has the highest molar conductivity.

The explanation for the incorrect answer

(A)$\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_5\mathrm{Cl}\right]C{l}_2$

1. $\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_5\mathrm{Cl}\right]C{l}_2$ has total three ions $2{\mathrm{Cl}}^{-}$ and a ${\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_5\mathrm{Cl}\right]}^{2+}$.
2. Thus, $\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_5\mathrm{Cl}\right]C{l}_2$has low molar conductivity than that of $\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_6\right]C{l}_3$.
3. Thus, it is an incorrect option.

(C)$\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_3{\mathrm{Cl}}_3\right]$

1. $\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_3{\mathrm{Cl}}_3\right]$ has only one ion when dissociated.
2. Thus, it has low molar conductivity than $\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_6\right]C{l}_3$.
3. Thus, it is also an incorrect option.

(D) $\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_4{\mathrm{Cl}}_2\right]Cl$

1. $\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_4{\mathrm{Cl}}_2\right]Cl$ has two ions that are ${\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_4{\mathrm{Cl}}_2\right]}^{+}$ and a ${\mathrm{Cl}}^{-}$.
2. The value of molar conductivity is low than that of $\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_6\right]C{l}_3$..
3. Thus, it is also an incorrect answer.

Thus, $\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_6\right]C{l}_3$has the highest molar conductivity. Therefore, option B is correct.