Given below are two statements: Statement I: For KI , molar conductivity increases steeply with dilution.…

Given below are two statements:

Statement I: For KI, molar conductivity increases steeply with dilution.

Statement II: For carbonic acid, molar conductivity increases slowly with dilution. In the light of the above statements, choose the correct answer from the options given below

  1. Statement I is correct and Statement II is incorrect
  2. Both Statement I and Statement II are false
  3. Statement I is true but Statement II is false
  4. Statement I is false but Statement II is true

Solution

For strong electrolytes, ∧m increases slowly with dilution and can be represented by the equation:

∧m=∧mo-A c12

It can be seen that if we plot ∧m against c12, We obtain a straight line with intercept equal to ∧m and slope equal to '-A'. The value of the constant 'A' for a given solvent and temperature depends on the type of electrolyte. KI is a strong electrolyte.

Weak electrolytes like carbonic acid and have lower degree of dissociation at higher concentrations and hence for such electrolytes, the change in ∧m with dilution is due to increase in the degree of dissociation and consequently the number of ions in total volume of solution that contains 1 mol of electrolyte. In such cases ∧m increases steeply on dilution, especially near lower concentrations. Therefore, ∧mo cannot be obtained by extrapolation of ∧m to zero concentration.

Asked in: JEE Main 2022 (27 Jul Shift 2)

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