Theory of experiment
Materials are usually classified as conductors, semiconductors, or insulators in terms of their behavior toward the flow of current. Conductors have very little resistance to the passage of current. Ohm’s law states that,

V = i R                      (1)

where V is the potential, i is the current and R is the resistance. The resistance depends upon the nature and geometry of the conductor.

R= ρ.l/A                   (2)

In the above equation, l is the distance, A is the area and ρ is the specific resistance. It is more convenient to focus attention on the conductance, L, which is inverse of the resistance, R, for when the conductor is in liquid state, and is expressed in mho or ohm-1. In terms of conductance equation (2) is written as

L= κ.A/l                   (3)

Where κ is the specific conductance, i.e., the conductance of a tube of material 1 cm long having a cross section of 1 cm2. The equivalent conductance (Λ) is defined as the specific conductance of a solution containing 1 gram equivalent of electrolyte.

Λ= κ/c                   (4)

where c is the electrolyte concentration (moles cm-3). The equivalent conductance of an electrolyte can be measured by using a conductivity cell. For any conductivity cell, the ratio l/A is a constant known as the cell constant, X, which is determined in every experiment.

The equivalent conductance of an electrolyte increases with dilution and reaches a limiting value for infinitessimally small concentration. This is called the equivalent conductance at infinite dilution and is denoted by Λ0 and can be obtained using the dependence of equivalent conductance on concentration at low conentrations. For strong electrolytes
Λ=Λ₀−K √c

Kohlrausch proposed that when complete dissociation exists in infinite dilution, each ionic species migrates independently. The Λ0 value can be then considered to be the sum of equivalent ionic conductances at infinite dilution

Λ₀= λ₀⁺+λ₀^-                  (9)

where λ₀⁺ and λ₀^- are the equivalent conductances at infinite dilution of the positive and negative ions respectively.

Kohlrausch additivity law can be used to obtain Λ₀ for a weak electrolyte, which can be further connected to the degree of dissociation α of the same as:

α= Λ/Λ₀

which can be related to the dissociation constant of a 1:1 weak acid as K=c.α²/1−α