The molar conductivity ( λ_m ) of KCl solutions at different concentrations at 298 K is plotted as shown in the figure given below:

Determine the value of λ⁰_m and A for KCl.

The plot of molar conductivity (λ_m) vs different C^1/2 values of KCL solutions given is a straight line.

• and from the equation

λ_m = λ⁰_m – A C^1/2 we can see that the intercept for the straight line( where C^1/2 = 0 ) is actually the limiting molar conductivity λ⁰_m (from the concept of y=mx + c, where c=the intercept )

the value of which can be determinedfrom the graph and is = 150.00 S Cm² mol^-1

• on the other hand, the slope of the graph is the value of A which can be determined by the concept y=mx + c, where m is the slope and

m=(y – c)/x,

• by taking the molar conductivity λ_m =147.2 for the C^1/2 = .034 from the graph,

A= - slope =

= - 82.35 S cm² mol^–1(mol/L^–1)-^1/2.