What is the Difference Between Equivalent Conductance and Molar Conductance

The key difference between equivalent conductance and molar conductance is that equivalent conductance is the conductance of an electrolyte that is divided by the number of equivalents of the electrolyte per unit volume, whereas molar conductance is the conductance of an electrolyte divided by the number of moles of the electrolyte.

Molar conductance is the conductance of all the ions furnished by one mole of an electrolyte present in a definite volume of the solution. Equivalent conductance is the conductance of a volume of a solution consisting of one equivalent weight of dissolved substance when it is placed between two parallel electrodes.

CONTENTS

1. Overview and Key Difference
2. What is Equivalent Conductance 
3. What is Molar Conductance
4. Equivalent Conductance vs Conductance in Tabular Form
5. Summary – Equivalent Conductance vs Molar Conductance

What is Equivalent Conductance?

Equivalent conductance is the conductance of a volume of a solution consisting of one equivalent weight of dissolved substance when it is placed between two parallel electrodes. The electrodes are placed with a 1 cm distance between them. It is large enough to contain the solution between them. It can be described as the net conductance of every ion that is produced from 1 gram equivalent of a particular substance. The calculation for this parameter is done as follows:

λ = kV

In this equation, λ is equivalent conductance, k is a constant, and V is the volume in milliliters given for 1 gram equivalent of the electrolyte we are using for this determination.

What is Molar Conductance?

Molar conductance is the conductance of all the ions furnished by one mole of an electrolyte present in a definite volume of the solution. The term molar conductivity refers to the property of having a molar conductance.

Molar conductivity is the conductivity of an electrolytic solution measured per unit molar concentration of the solution. We can determine this as the conductivity of the electrolytic solution divided by the molar concentration of the electrolyte. Therefore, we can give the molar conductivity in the following equation:

Molar conductivity = k/c

k is the measured conductivity of the electrolytic solution, and c is the concentration of the electrolytic solution.

When considering the measurement of molar conductivity, the SI unit for measurement of this property is Siemens meters squared per mole. Then the unit is given as S m2 mol-1. However, most often, the unit for this property is S cm2 mol-1.

What is the Difference Between Equivalent Conductance and Molar Conductance?

Molar conductance is the conductance of all the ions furnished by one mole of an electrolyte present in a definite volume of the solution. Equivalent conductance, on the other hand, is the conductance of a volume of a solution consisting of one equivalent weight of dissolved substance when it is placed between two parallel electrodes. The key difference between equivalent conductance and molar conductance is that equivalent conductance is the conductance of an electrolyte that is divided by the number of equivalents of the electrolyte per unit volume, whereas molar conductance is the conductance of an electrolyte divided by the number of moles of the electrolyte.

The below infographic presents the differences between equivalent conductance and molar conductance in tabular form for side by side comparison.

Summary – Equivalent Conductance vs Molar Conductance

Equivalent conductance and molar conductance are two types of conductivities. The key difference between equivalent conductance and molar conductance is that equivalent conductance is the conductance of an electrolyte that is divided by the number of equivalents of the electrolyte per unit volume, whereas molar conductance is the conductance of an electrolyte divided by the number of moles of the electrolyte.

Reference:

1. “Molar Conductivity.” An Overview | ScienceDirect Topics.

Image Courtesy:

1. “Conductivity (electrolytic)2” By Karishma50 – Own work (CC BY-SA 4.0) via Commons Wikimedia

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