Equivalent conductance of 1M ${\mathrm{CH}}_3\mathrm{COOH}$ is $1010 {\mathrm{ohm}}^{-1} {\mathrm{cm}}^2 {\mathrm{equi}}^{-1}$and that at infinite dilution is  $200 {\mathrm{ohm}}^{-1} {\mathrm{cm}}^2 {\mathrm{equi}}^{-1}.$ Hence the % ionization of ${\mathrm{CH}}_3\mathrm{COOH}$ is