Question

Suppose 0.010 mol of each of the following compounds is

dissolved (separately) in 1.0 L water: ${\mathbf{KNO}}_3\mathbf{,}\mathbf{\left[}\mathbf{CO}{\mathbf{\left(}{\mathbf{NH}}_3\mathbf{\right)}}_6\mathbf{\right]}{\mathbf{Cl}}_3\mathbf{,}{\mathbf{Na}}_2\mathbf{\left[}{\mathbf{PtCl}}_6\mathbf{\right]}\mathbf{,}\mathbf{\left[}\mathbf{Cu}{\mathbf{\left(}{\mathbf{NH}}_3\mathbf{\right)}}_2{\mathbf{Cl}}_2\mathbf{\right]}$. Rank the resulting four solutions in order of conductivity, from lowest to highest.

Short answer

$\left[\text{Cu}{\left({\text{NH}}_{\text{3}}\right)}_{\text{2}}{\text{Cl}}_{\text{2}}\right]<{\text{KNO}}_{\text{3}}<{\text{Na}}_{\text{2}}\left[{\text{PtCl}}_{\text{6}}\right]<\left[\text{CO}{\left({\text{NH}}_{\text{3}}\right)}_{\text{6}}\right]{\text{Cl}}_{\text{3}}$

Step-by-step solution

Conductivity

Conductivity, also known as“specific conductance (conductance at the specified condition),” is the reciprocal of resistivity $\left(\text{ρ}\right)$and is represented as follows:

$\mathbf{Conductivity}\mathbf{=}\frac{1}{\rho }$

Step 2:Order of conductivity

The conductivity of the compound dissolved will be greater if it forms more ions in the solution, as conductivity is directly dependent on the number of ionsproduced in the solution.

KNO₃ forms two ions in the solution.

$\left[\text{CO}{\left({\text{NH}}_{\text{3}}\right)}_{\text{6}}\right]{\text{Cl}}_{\text{3}}$forms four ions in the solution.${\text{Na}}_{\text{2}}\left[{\text{PtCl}}_{\text{6}}\right]$ forms three ions in the solution

$\left[\text{Cu}{\left({\text{NH}}_{\text{3}}\right)}_{\text{2}}{\text{Cl}}_{\text{2}}\right]$not form any ions in the solution.

Therefore the conductivity order from the lowest to highest of the given compound is as follows:

$\left[\text{Cu}{\left({\text{NH}}_{\text{3}}\right)}_{\text{2}}{\text{Cl}}_{\text{2}}\right]<{\text{KNO}}_{\text{3}}<{\text{Na}}_{\text{2}}\left[{\text{PtCl}}_{\text{6}}\right]<\left[\text{CO}{\left({\text{NH}}_{\text{3}}\right)}_{\text{6}}\right]{\text{Cl}}_{\text{3}}$