Test: Kohlrausch’s Law - NEET MCQ

1. Nature of Electrolyte: The type of electrolyte (strong or weak) affects conductivity. Strong electrolytes, like sodium chloride, dissociate completely into ions, providing higher conductivity. Weak electrolytes, like acetic acid, partially dissociate, resulting in lower conductivity.

2. Nature of Solvent: The solvent affects how well the electrolyte dissociates into ions. For example, water is a good solvent for many electrolytes, while other solvents may not dissolve electrolytes as effectively, impacting the solution’s conductivity.

3. Temperature: Increasing the temperature generally increases the conductivity of a solution. This is because higher temperatures increase the kinetic energy of the molecules, leading to more dissociation of the electrolyte and greater mobility of ions.

Thus, all these factors—nature of the electrolyte, nature of the solvent, and temperature—play a role in determining the conductivity of a solution.

The correct answer is option A

Conducting power of one mole of ions at a given temperature at infinite dilution is known as limiting molar conductivity. In other words, When the concentration of the electrolyte approaches zero, the molar conductivity is known as limiting molar conductivity.

The correct answer is Option D.
 
The molar conductivity increases with decrease in concentration both, for weak and strong electrolytes.

This is because the total volume, V, of a solution containing one mole of electrolyte also increases. It has been found that a decrease in k on dilution of a solution is more than compensated by an increase in its volume.

The correct answer is Option B.

Λ_m of AB = 145.05 cm²mol^-1
Λ_m of AB = Λ^oA + Λ^oB (Kohlraush’s law)
      145    = Λ^oA + Λ^oB --- (1)

 Λ_m of CB = 110.10 Scm²mol^-1

 Λ_m of CB = Λ^oC + Λ^oB 
    110.1    =  Λ^oC + Λ^oB --- (2)

Eqn (1) - Eqn (2)
 
145 - 110.1 = Λ^oA + Λ^oB - Λ^oC + Λ^oB
34.9 = Λ^oA - Λ^oC
34.9 = 73.5 - Λ^oC
Λ^oC = 73.5 - 34.9 
       = 38.6 Scm²mol^-1

The correct answer is option A

Kohlrausch's law states that the equivalent conductivity of an electrolyte at infinite dilution is equal to the sum of the conductances of the anions and cations. If a salt is dissolved in water, the conductivity of the solution is the sum of the conductances of the anions and cations.
Hence, at infinite dilution the ionic conductivity of ions is additive.

The correct answer is option C
Conductivity of a solution is equal to the conductance of a solution of 1cm length and cross section area of 1 square cm it may also be defined as the conductance of one centimeter cube of the conductor .It is represented by the symbol kappa (k) mathematically we can write
K = G×G⋅ conductance ,G⋅=cell constant
The unit of K is ohm−1cm−1 or S cm−1
The conductivity K of an electrolytic solution depends on the concentration of the electrolyte nature of solvent and temperature .molar conductivity molar conductivity of a solution at a given concentration is the conductance of the volume v of solution containing one mole of electrolyte between two electrodes with area of cross section a and distance of unit length.

The correct answer is Option D.
 
Kohlrausch's law states that the equivalent conductivity of an electrolyte at infinite dilution is equal to the sum of the conductances of the anions and cations. When the concentration of the electrolyte approaches zero, the molar conductivity is known as limiting molar conductivity, Ëm°

The correct answer is option  B
In case of the weak electrolyte it is not possible to calculate the molar conductivity at infinite dilution by extrapolation of the graph between the molar conductivity and the concentration,because there is large variation between them. As you can see from the graph:-

In case of weak electrolytes conductivity can be calculated by Kohlrausch law.