Question

Solutions of two electrolytes X and Y are diluted. Molar conductivity of X increases 25 times whereas that of Y increases 1.5 times. Which one is a stronger electrolyte?

• A. X
• B. Y
• C. Both X and Y
• D. None of the above

Hint:

Strong electrolytes are almost fully ionized even at higher concentrations, so their molar conductivity changes little on dilution.

Answer 1

The Correct Option is B

Step 1: When a solution is diluted, the molar conductivity (\( \Lambda_m \)) of an electrolyte increases because the degree of ionization increases.
Step 2: For a weak electrolyte, dilution greatly increases ionization, so the increase in molar conductivity is significant.
For a strong electrolyte, it is already almost completely ionized, so dilution only slightly increases molar conductivity.
Step 3: Since the molar conductivity of X increases 25 times, it must be a weak electrolyte.
The molar conductivity of Y increases only 1.5 times, so Y must be a strong electrolyte.