The conductivity (k) of a solution is directly linked to the number and type of ions dissolved in it. Strong electrolytes and ions with higher charges conduct electricity more efficiently. Below is a clear, step‑by‑step guide to determine k using molar conductivity and concentration.
Λm is a constant that represents the conductivity of an infinitely diluted solution. It is the sum of the molar conductivities of the cation and anion, with the anion’s value subtracted due to its negative sign. Theoretical values are typically sourced from reference tables.
Record the total volume of the solution in liters, after the electrolyte has been fully dissolved. Accuracy here is critical because it directly influences concentration calculations.
Weigh the electrolyte in grams, then divide by its molecular weight to obtain the number of moles (n).
Concentration is expressed as moles per liter: C = n / V, where V is the volume from Step 2.
Multiply the molar conductivity by the molar concentration: k = Λm × C. The result is the solution’s conductivity in S·m⁻¹.
For strong electrolytes, simply multiply molar conductivity by molar concentration. Weak electrolytes require the dissociation constant (α) to adjust Λm before applying the same formula.
At high concentrations, even strong electrolytes may behave like weak electrolytes due to ion pairing or precipitation. Temperature affects both solubility and viscosity, altering conductivity. When mixing multiple electrolytes, be aware that cross‑interactions between ions can form weak electrolyte pairs, complicating the calculation.
