NEETChemistryElectrochemistry
For strong electrolytes, the molar conductivity ( _ m ) varies with concentration according to the linear equation _ m = _ m ^ - A c . Which of the following statements correctly describes the behaviour of a weak electrolyte, such as acetic acid, under similar dilution conditions?
Options
- AIts molar conductivity increases steeply at lower concentrations, and its _ m ^ cannot be obtained by extrapol
- BIt follows the same linear equation as strong electrolytes, but with a significantly larger value of the const
- CIts molar conductivity decreases upon dilution because the degree of dissociation is suppressed at lower conce
- DIts _ m versus c plot is a straight line that passes through the origin.
Correct answer
A. Its molar conductivity increases steeply at lower concentrations, and its _ m ^ cannot be obtained by extrapol
Step-by-step solution
For weak electrolytes like acetic acid, the degree of dissociation increases significantly upon dilution. As a result, the number of ions in the solution increases, leading to a steep increase in molar conductivity ( _ m ) at lower concentrations. Because of this steep curve, the plot of _ m versus c is not linear. Consequently, the limiting molar conductivity ( _ m ^ ) for weak electrolytes cannot be obtained by simply extrapolating the curve to zero concentration (as is done for strong electrolytes). Instead, Koh