Question

A 0.05 M NaOH solution offered a resistance of 31.6 ohms in a conductivity cell. If the cell constant of the conductivity cell is 0.378 cm⁻¹, determine the molar conductivity of sodium hydroxide solution at this temperature.

Answer 1

Given:

Concentration of NaOH (C) = 0.05 mol/L

Resistance (R) = 31.6 Ω

Cell constant (K) = 0.378 cm⁻¹

To find:  

Specific conductivity (κ) = ?

Molar conductivity (Λ_m) = ?

Calculations:

`kappa = "Cell constant"/"Resistance"`

= `0.378/31.6`

= 0.01196 Ω⁻¹ cm⁻¹

`Lambda_m = (kappa xx 1000)/C`

= `(0.01196 xx 1000)/0.05`

= `11.96/0.05`

= 239.2 S cm² mol⁻¹