Question

Based on the data given above, give plausible reason for the variation of conductivity and molar conductivity with concentration.

Concentration of KCl solution (mol/L)	Conductivity at 298.15 K (S cm-1)	Molar Conductivity at 298.15 K (S cm2 mol-1)
1.000	0.1113	111.3
0.100	0.0129	129.0
0.010	0.00141	141.0

Hint:

In dilute solutions, the molar conductivity increases with concentration due to higher ion dissociation. At high concentrations, the ion interactions reduce conductivity.

Answer 1

As concentration increases, the ions in the solution are more concentrated, leading to an increase in the number of ion collisions. This reduces the mobility of the ions and causes a decrease in the molar conductivity. Conductivity also decreases with concentration because of the reduction in ion mobility.
However, at very high concentrations, ions may also begin to interact with each other, further reducing the ion mobility.