Observations via a video camera of the behavior of the bubbles produced in a chlor-alkali membrane cell with parallel-plate electrodes during sodium chloride electrolysis allowed us to justify the use of 1D model for the calculation of current density distribution. Experimental current density measurements were determined using segmented electrode method. The modeling was done in the case of secondary distribution. It takes into account the effective conductivity of gas-liquid mixture. Solving the modified Laplace equation was undertaken using commercial finite element method software. The numerically computed curves and the experimental measurements are in a good agreement.