Question

The resistance of a 0.5 M solution of an electrolyte in a cell was found to be 45 ohm. Calculate the molar conductivity of the solution if the electrodes in the cell are 2.2 cm apart and have an area of 3.8 cm².

Answer 1

Cell constant = `l/A`

= `2.2/3.8`

= 0.579 cm⁻¹

Specific conductivity (κ) = Cell constant × Conductance

= `"Cell constant" xx 1/"Resistance"`

= `0.579 xx 1/45` ohm⁻¹ cm⁻¹

Molar conductivity is given by

`Lambda_m = kappa xx 1000/M`

= `0.579/45 xx 1000/0.5`

= 25.73 ohm⁻¹ cm² mol⁻¹

∴ The molar conductivity of the given solution is 25.73 ohm⁻¹ cm² mol⁻¹.