Molar Conductivities and their variation with Concentration

Molar conductivity refers to the conductivity of an electrolyte measured per unit in molar concentration. A function of the ionic strength of a solution is referred to as molar conductivity. Molar conductivities are not constant.Conductivity and Molar Conductivity

The difference between conductivity and molar conductivity is the ability of molar conductivity to measure an electrolyte for conducting electricity. 

Specific Conductance 

Specific conductivity is a unit of Sm−1. 

 Specific Conductance, κ = Conductance (G) x Cell Constant (l/A)

Molar conductance is interpreted as conductance due to one mole of the electrolyte, which exists in volume V of the solution. 

Electrolyte Concentration =c M

The Formula of Molar Conductivity

The representation of molar conductivity is: 

Formula –  Λm = κ / C

• Here, κ refers to specific conductivity

• C refers to concentration in mole per liter

The electrolytic solution’s molar conductivity is the conductance of the volume of the solution that consists of a unit mole of electrolyte, which is generally placed in the middle at a distance of one centimeter apart.  

Variation of Molar Conductivity with Concentration

Mainly when there is an increase in concentration, the molar conductivity decreases. When there is an increase in dilution, the electrolytic conduction also increases. In other words, it can be said that the greater the number of ions are present, the greater the conductance is. Whereas with the dilution, these are produced in solution to increase the dilution on conductance. 

The electrolyte’s conductivity lessens, with the decrease in the concentration for both the weak and the strong electrolytes; the molar conductivity eventually increases with the decrease in concentration. 

The specific conductivity or conductance decreases in dilution, whereas the molar conductivity increases. It is the conductance of a one-centimeter cube of solution.

Therefore, while diluting the solution, the ions concentration per centimeter cube decreases, which is why the conductivity also decreases. 

Molar conductivity increases on dilution due to the point that is the product of conductivity (K) and the volume (V) containing one mole of the electrolyte of the solution. 

Formula –  Λ = κ × V

Conductivity decreases in the dilution, but the volume that consists of one mole of electrolyte boosts. On dilution, the increase in volume is more tremendous than the reduction in conductivity. So, with dilution, the molar conductivity boosts. 

Molar Conductivity for Strong Electrolytes

In Strong electrolytes, molar conductivity expands deliberately. 

• When the concentration moves towards zero, the dilution is infinite at that time.  

• When the concentration of the molar conductivity moves towards zero, the process is referred to as infinite dilution with molar conductivity.  

Molar Conductivity for Weak Electrolytes

• It dissociates to a much lesser extent as compared to weak electrolytes. 

• Molar conductivity is competitively low with the weak electrolytes. 

Conclusion

Molar conductivity is explained as the conductivity of an electrolyte solution, which is divided by the electrolytes’ molar concentrations. Both the molar conductivity of weak and robust electrolytes increases with the decrease in dilution. Nonetheless, an increased dilution causes dissociation of other electrolytes into ions, eventually increasing the total number of effective ions in the concentration. An electrolytic solution’s molar conductivity is the conductance of the volume of the solution that consists of a unit mole of electrolyte, which is generally placed in the middle at a distance of one centimeter apart.