Equivalent Conductivity Formula

What is the Formula for Equivalent Conductivity?

What is equivalent conductivity? How is it different from Molar Conductivity Formula?

Equivalent conductivity is the conductance of a volume of solution containing one equivalent of an electrolyte. It is denoted by the symbol ∧

Consider the volume of a V cm3 solution having one electrolyte equivalent. It has the same conductance as comparable conductance.

Specific conductance is the conductance exhibited by a 1 cm3 solution containing this electrolyte (between two electrodes with a cross-sectional area of 1 cm2 separated by a distance of 1 cm). Here, we will define equivalent conductivity in detail.


Equivalent Conductance Definition in Mathematical Terms 

Equivalent conductance definition and formula in mathematical terms:

the conductance of V cm3 --------- Λ

the conductance of 1 cm3 --------- κ

Therefore:

Λ = κ.V  ---------- equation (3)

We know that the normality (N) of a solution is given by the equation below

N = n/V 1000

Equivalent conductance formula: 

V = 1000/n

For the above electrolytic solution, no. of equivalents, n = 1.

V = K x 1000/n

Hence

relation between V and N

Equivalent conductance can be written as 

Λ = k x V

Units of Λ: units of equivalent conductance

m2 . ohm-1. equiv-1 = cm2 . mho. equiv-1

or 

m2 . Siemens. equiv-1


Molar Conductivity

Molar conductivity is the conductance of a solution containing one mole of electrolyte or a function of a solution's ionic strength or salt concentration. As a result, it is not a constant.

In other words, molar conductivity is the total conducting power of all the ions generated when a mole of electrolytes is dissolved in a solution. Molar conductivity is a feature of an electrolyte solution that is primarily used to determine an electrolyte's efficiency in conducting electricity in a solution. As a result, it is not a constant.


Molar Conductivity Formula

The expression used to represent molar conductivity mathematically is given below.

μ = K / C 

μ = K / C  = K / C 

K is the specific conductivity, while c is the mole per liter concentration.

The molar conductivity of an electrolytic solution is defined as the conductance of a volume of solution containing a unit mole of electrolyte put between two electrodes of unit area cross-section. The molar conductivity unit is Sm2mol-1.


Relation Between Equivalent Conductance Formula and Molar Conductance

The relation between equivalent conductance and molar conductance can be given by:

 μ = Λ x equivalent factor of an electrolyte

The total charge on either anions or cations present in one formula unit of the electrolyte is usually the equivalent factor. In the case of acids, it can be equal to basicity, while in the case of bases, it can be equal to acidity.


What is The Formula For Equivalent Conductivity And How is It Different From The Molar Conductivity Formula?

The conductance of all the ions produced by one gram equivalent of an electrolyte in a given solution is known as equivalent conductance.

k V = equivalent conductance

Where V is the volume in mL that contains 1 g of electrolyte equivalent.

Molar conductance is the total conductance of all the ions produced by ionisation of 1 g mole of an electrolyte in V mL of solution.. It is denoted by the symbol l.

Molar conductance = kV

Where V is the volume in mL of the electrolyte having 1 g mole. If c is the solution's concentration.

Formula 

Equivalent conductance= Molar conductance/n


Factors Affecting Equivalent Conductivity

  1. Temperature: Because the extent of ionization increases with increasing temperature, the conductance of an electrolyte solution increases.

  2. Strong electrolytes undergo complete ionisation and so have larger conductivities because they produce a greater number of ions.

  3. Weak electrolytes, on the other hand, undergo partial ionisation and so have poor conductivities in their solutions.

  4. Ionic size and mobility: As the size of an ion increases, its mobility reduces, and its conductivity lowers as well.

  5. Ionic mobility is diminished in more viscous solvents due to the nature of the solvent and its viscosity. As a result, the conductivity decreases.

  6. As the number of ions per unit volume grows, the specific conductance increases with the increase in solution concentration.

  7. However, because the extent of ionisation increases with decreasing concentration (i.e. dilution), both the equivalent conductivity and molar conductance increase.


Solved Example: 

Calculate Molar Conductivity of KCl Solution?

Given: 

Molarity (M) = 0.30M

Conductivity at 298 K (k) = 0.023 S cm-

Solution:

Molar conductivity = (1000 × k) /M

= (1000 × 0.023) / 0.30

= 76.66 cm² mol⁻¹

 So molar conductivity of KCl solution is 76.66 cm² mol⁻¹.


Conclusion 

The conductivity of a volume of solution containing one equivalent of an electrolyte is called equivalent conductivity. The conductance property of a solution containing one mole of electrolyte, or a function of a solution's ionic strength or salt concentration, is known as molar conductivity. As a result, it isn't always the same. In other words, when a mole of electrolyte is dissolved in a solution, molar conductivity is the total conducting power of all the ions created.

Equivalent conductance= Molar conductance/n

FAQs (Frequently Asked Questions)

1. In Chemistry, What is Equivalent Conductance?

Ans: The conductance of an electrolyte's equivalent conductance is defined as the conductance of a volume of solution containing one equivalent weight of dissolved substance when placed between two parallel electrodes 1 cm apart and large enough to contain the entire solution between them.

2. What is the Equivalent Conductivity Formula? Define Equivalent Conductance In Detail.

Ans: The conductance of all the ions produced by one gram equivalent of an electrolyte in a given solution is known as equivalent conductance. k V = equivalent conductance Where V is the volume in mL that contains 1 g of electrolyte equivalent.

3. How Do You Calculate Equivalent Conductivity From Molar Conductance?

Ans: It takes two moles of NaOH to neutralize one mole of H2SO4 when we totally neutralize it with NaOH. As a result, the corresponding weight is half the molar mass, which is 49.04 for H2SO4. As a result, the molar conductance of H2SO4 will be twice that of the equivalent conductance.