What should be the order of specific conductance (κ) of floride, chloride and bromide ions?

The equivalent conductance order is $\ce{Br-} > \ce{Cl-} > \ce{F-}$.


$$Λ = \frac{κ}{c},$$


so $Λ$ is proportional to specific conductance?


But in ion chromatography we get peak area where $\ce{F-} > \ce{Cl-} > \ce{Br-}$ (specific conductance, μS/cm) for the same concentration, let us say 1 ppm.


Why?




ppm is ambiguous quantity, it can be v/v, w/v,w/w,n/n. 


By other words, all 1 ppm very probably is not the same molar concentration, unless it is n/n ppm, relating itself to the molar amount of the solution.


$\Lambda = \kappa /c$ is correct, but $c$ must be the molar concentration.


$$\Lambda[\pu{Sm^2mol^-1}]=\frac{M[\pu{g/mol}]}{c[\pu{ppm as g/m^3}]}\cdot \kappa[\pu{S/m}]$$


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