Question

How to test the conductivity of weak electrolytes

Answer 1

It is possible to differentiate between strong and weak electrolytes by measuring their electrical conductance. Strong electrolytes follow Kohlrausch's law, whereas weak electrolytes are described by Ostwald's dilution law.
For a strong electrolyte which is made up of a salt with the formula MX dissolving in water:

MX(aq) ⇋ M+(aq)+ X-(aq)

the equilibrium positionlies very far to the right, there are many ions in solution

the value of the equilibrium constant, K, for the dissociation is large

If the substance completely dissociates in the solvent, that is, if the degree of dissociation is 100%, we may write this as a reaction which occurs in only one direction:

MX → M+(aq) + X-(aq)

A weak electrolyte has a low degree of dissociation (ionisation) in solution:

For a weak electrolyte made up of a compound with the formula ZX dissolving in water:

ZX(aq) ⇋ Z+(aq) + X-(aq)

the equilibrium positionlies very far to the left, there are very few ions in solution

the value of the equilibrium constant, K, for the dissociation is small.