The molar conductivity of a $0.050 M$ solution of a strong electrolyte is $40.0 S c m^{2} mo l^{- 1}$ . In a conductivity cell whose parallel electrodes each have area $1.50 c m^{2}$ , this solution shows a resistance of $360 Ω$ . The distance between the electrodes, in cm (two decimals), is

Numerical answer type, answer in cm, tolerance 0.02.

Answer: 1.08 cm

First recover the conductivity:

κ = Λ_{m} c /1000 = 40.0 \times 0.050/1000 = 2.0 \times 1 0^{- 3} S c m^{- 1}

. Cell constant

G^{*} = κ R = 2.0 \times 1 0^{- 3} \times 360 = 0.72 c m^{- 1}

. Since

G^{*} = l / A

l = 0.72 \times 1.50 = 1.08 cm