The invention includes an electrolytic cell for gas-developing or gas-consuming electrolytic reactions and processes, and an electrolysis process therefor. According to the invention, the capillary slit electrode has conduits enabling the separate flow of reaction gas and electrolyte/permeate in the electrode. The electrode is preferably hydrophilic in a narrow internal region for mounting on a separator, while elsewhere it is hydrophobic. Thus electrolyte/permeate penetrates only into the region of the capillary slit electrode near the separator, while the region away from the separator remains free of electrolyte/permeate, so facilitating the unimpeded flow of the reaction gas. The invention is applicable especially in electrolytic cells for chlor-alkali or hydrogen electrolysis, and in the construction of cells for the generation of power.