Question

The resistance of 0.01 N NaCl solution is 200 Ω at 25°C. Cell constant of the conductivity cell is unity. Calculate the equivalent conductance of the solution.

Answer 1

Given:

Resistance R = 200 Ω

Cell constant = 1 cm⁻¹

Normality N = 0.01 N

To calculate the equivalent conductance (Λ_eq), we use the formula:

Λ_eq​ = κ × 1000/N    ...(i)

κ = specific conductance (S cm⁻¹) = cell constant / resistance

N = normality of the solution (eq/L)

We know that

`kappa = "Cell constant"/R`

= `1/200`

κ = 5.0 × 10⁻³ S cm⁻¹

Putting these values in equation (i), we get

`Lambda_"eq" = (5.0 xx 10^-3 xx 1000)/0.01`

= `5.0/0.01`

Λ_eq = 500 S cm² eq⁻¹

∴ The equivalent conductance of the solution is 500 S cm² eq⁻¹