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Kohlrausch’s research was centered on determining how electricity was conducted in solutions. In his investigations to establish whether Ohm’s law also applied to second class conductors, he was the first scientist to utilize alternating current. In this way, he prevented the deposition of decomposition products on the electrodes and obtained highly precise results in his measurements. He used a telephone to monitor the process. The result was that Ohm’s law also found to apply to dissolved electrolytes. From 1875 to 1879, he examined numerous salt solutions, acids and solutions of other materials. Overall, Kohlrausch was involved in the measurement of electrical, magnetic and electrochemical phenomena for almost 50 years.
Kohlrausch’s Law on the independence of migrating ions: The molar conductivity Λ of an electrolyte equals the sum of the molar conductivities of the cations and the anions;
ν = no. of anions or cations.
| Λ = v + · Λ + + v - · Λ - |
Kohlrausch’s Square Root Law: For strong electrolytes with sufficient dilution, the molar conductivity Λc of an electrolyte of the concentration c is a linear function of the root of the concentration c0.
Λ∞ = molar conductivity at infinite dilution;
A = constant which is a function of the valence of the salt.
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