The conductivity of sodium chloride at 298 K has been determined at different concentrations and the results are given below :
ConcentrationM0.0010.0100.0200.0500.10010−2×kSm−11.23711.8523.1555.53106.74
Calculate λm for all concentrations and draw a plot between λm and C12 Find the value of λ∘m.
1 S cm−1100 S m−1=1 (Unit conversion factor)
Conc.(M)C12(M12)k(Sm−1)k(Scm−1)λcm=1000×kMolarity(S cm2 mol−1)10−30.031621.237×10−21.237×1010−51000×1.237×10−410−3=123.710−20.10011.85×10−211.85×10−41000×11.85×10−410−2=118.52×10−20.14123.15×10−223.15×10−41000×23.15×10−42×10−2=115.85×10−20.22455.53×10−255.53×10−41000×55.53×10−45×10−2=111.110−10.316106.74×10−2106.74×10−41000×106.74×10−410−1=106.7
λ∘m = Intercept on the λcm axis = 124.05 S cm2mol−1