The degree of dissociation ($\alpha$) of a weak electrolyte is the ratio of its molar conductivity at a given concentration ($\Lambda_m^c$) to its limiting molar conductivity at infinite dilution ($\Lambda_m^\infty$).

Given: Molar conductance at concentration $c$, $\Lambda_m^c = 9.54 \text{ ohm}^{-1} \text{ cm}^2 \text{ mol}^{-1}$ Molar conductance at infinite dilution, $\Lambda_m^\infty = 238 \text{ ohm}^{-1} \text{ cm}^2 \text{ mol}^{-1}$

Degree of dissociation ($\alpha$) $= \frac{\Lambda_m^c}{\Lambda_m^\infty}$ $\alpha = \frac{9.54}{238} = 0.04008$

To find the percentage degree of ionisation: $\alpha \% = 0.04008 \times 100\% = 4.008\%$