The conductance of a 0.0015M aqueous solution of a weak monobasic acid was determined by using a conductivity cell consisting of platinized Pt electrodes. The distance between the electrodes is 120 cm with an area of cross-section of 1cm². The conductance of this solution was found to be 5 × 10^-7S. The pH of the solution is 4. The value of limiting molar conductivity (?om) of this weak monobasic acid in an aqueous solution is Z × 10² S cm^-1 mol^-1. The value of Z is.