NEETChemistryElectrochemistry
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): The limiting molar conductivity ( _m^ ) of a weak electrolyte like acetic acid cannot be determined accurately by extrapolating the plot of _m against c to zero concentration. Reason (R): The degree of dissociation of a weak electrolyte decreases significantly upon dilution. In the light of the abo
Options
- ABoth (A) and (R) are true and (R) is the correct explanation of (A)
- BBoth (A) and (R) are true but (R) is not the correct explanation of (A)
- C(A) is true but (R) is false
- D(A) is false but (R) is true
Correct answer
C. (A) is true but (R) is false
Step-by-step solution
Assertion (A) is true. For weak electrolytes, the plot of _m against c shows a steep increase in molar conductivity at low concentrations. Therefore, it does not yield a straight line that can be extrapolated to zero concentration to find _m^ . Reason (R) is false. According to Ostwald's dilution law, the degree of dissociation of a weak electrolyte increases significantly upon dilution, which is the actual reason for the steep increase in molar conductivity at lower concentrations. Therefore, (A) is true but (R) i