# 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?

• Are they of the same concentration? As without that knowledge, the order of the conductivity ( specific conductance ) is undefined. – Poutnik Jun 2 '19 at 6:43
• yes sir. lets say 1ppm – ggs Jun 2 '19 at 7:25

$$\Lambda = \kappa /c$$ is correct, but $$c$$ must be the molar concentration.
$$\Lambda[\pu{Sm^2mol^-1}]=\frac{M[\pu{g/mol}]}{c[\pu{ppm as g/m^3}]}\cdot \kappa[\pu{S/m}]$$