Question

Give answers: (i) Why does the conductivity of any solution decrease with dilution?
(ii) Conductivity of 0.20 M KCl solution at 298 K is 0.248 S cm\(^{-1}\). What will be its molar conductivity?

Hint:

Conductivity decreases with dilution, but molar conductivity increases due to increased ion mobility.

Answer 1

(i) Reason.
Conductivity decreases with dilution because the number of ions per unit volume decreases, reducing total current carrying capacity.
(ii) Calculation.
Molar conductivity: \[ \Lambda_m = \frac{\kappa \times 1000}{C} = \frac{0.248 \times 1000}{0.20} = 124 \, S \, cm^2 \, mol^{-1} \] Step 3: Conclusion.
(i) Fewer ions per volume → lower conductivity.
(ii) Molar conductivity =
124 S cm\(^2\) mol\(^{-1}\).