Question

The conductivity of sodium chloride at 298 K has been determined at different concentrations and the results are given below:

Concentration/M	0.001	0.010	0.020	0.050	0.100
102 × κ/S m−1	1.237	11.85	23.15	55.53	106.74

Calculate `∧_"m"`for all concentrations and draw a plot between `∧_"m"`and `"c"^(1/2)`. Find the value of `∧_"m"^0`.

Answer 1

Concentration (M)	C1/2 (M1/2)	κ(S m−1)	κ(S cm−1)	`∧_"m" = (κ xx 1000)/"M"` (S cm2 mol−1)
0.001	0.0316	1.237 × 10−2	1.237 × 10−4	`∧_"m" = (1.237 xx 10^-4 xx 1000)/0.001` = 123.7
0.010	0.100	11.85 × 10−2	11.85 × 10−4	`∧_"m" = (11.85 xx 10^-4 xx 1000)/(0.010)` = 118.5
0.020	0.141	23.15 × 10−2	23.15 × 10−4	`∧_"m" = (23.15 xx 10^-4 xx 1000)/0.020` = 115.8
0.050	0.224	55.53 × 10−2	55.53 × 10−4	`∧_"m" = (55.53 xx 10^-4 xx 1000)/(0.1050)` = 111.1
0.100	0.316	106.74 × 10−2	106.74 × 10−4	`∧_"m" = (106.74 xx 10^-4 xx 1000)/(0.100)` = 106.7

When the straight line is drawn backwards, it meets the `∧_"m"`axis at 124.0 S cm² mol⁻¹, which is the value of `∧_"m"^0`.