Question

Why limiting molar conductivity of CH₃COOH cannot be determined experimentally?

Answer 1

Hint: Molar conductivity is defined as the conducting power of ions when one mole of electrolytes is dissolved in a solution. According to Kohlraush’s law, the equivalent conductivity at infinite dilution is equal to the sum of the conductance of anions and cations of an electrolyte.

Complete Step by Step Solution:
The molar conductivity of a solution comprises one mole of the electrolyte which is variable. Molar conductivity is the conductance per mole of electrolyte, that is separated by a one-centimetre distance.

Kohlraush’s law can be defined as the equivalent conductivity of an electrolyte at infinite dilute is equal to the total conductance of the anions and cations.
The molar conductivity of a strong electrolyte at infinite dilution can be calculated by extrapolation as the plot between molar conductivity and the square root is linear.

In a weak electrolyte, the molar conductivity at an infinite solution cannot be determined experimentally and by extrapolation, as the plot obtained is not linear, the value of molar conductivity is very high at an infinite solution that cannot be determined.
The dissociation of weak electrolytes increases with dilution and keeps on increasing even on infinite dilution.

Thus, the limiting molar conductivity of acetic acid cannot be determined experimentally.

Note: Kohlraush’s law helps in predicting the limiting molar conductivity of electrolytes. Weak electrolytes have a low value of molar conductivities and a low value of the degree of dissociation for higher concentrations. It can be calculated by the dissociation of salts that are sparingly soluble.