TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The apparatus includes a facility for contacting and reacting the metal hydroxide with the acid gas within the gas mixture thus reducing the concentration of the acid gas in the gas mixture, where the gas mixture is from a natural or artificial source including air or waste gas and the chemical reaction resulting in production of metal salt. The apparatus further comprises the facility for periodically or continuously removing the metal salt from the apparatus, where the facility is a drain, pump, vent, settling pond, evaporation pond, or other means for removing metal salt from the solution or container. In the apparatus: the facility is a naturally occurring, artificial, or manufactured gas-hydroxide contactor; the gas is an oxide of carbon, sulfur or nitrogen, or hydrogen sulfide; the naturally occurring gas-hydroxide contactor is a natural water body into which the metal hydroxide is added and whose surface contacts and reacts with the acid gas in the gas mixture; the pH of the water solution in which the metal salt is formed is maintained at less than or equal to 9, preferably 6-9; an ion concentration is naturally present in the water solution; the water solution is derived from the ocean, naturally saline surface water or ground water, saline waste water or any other water solution whose ion concentration is naturally allows electric current to pass in the current path to allow the splitting of water or contained or produced in the ocean or in natural or artificial water body e.g. a bay, lagoon, lake, pond, reservoir, river, stream, or underground water body or aquifer; the ion concentration is achieved or maintained by the addition of ions to the water solution or by enriching ions in the water solution via water evaporation, electrodialysis, pressure dialysis, or by other means; electricity is derived from fossil energy e.g. coal, natural gas or oil, or from a low- or no-carbon dioxide emitting generation source (wind, solar, hydro, wave, tidal, ocean thermal, geothermal, geochemical, biochemical, biomass, or nuclear energy); the water splitting results in hydrogen (704) gas which is produced at the cathode, and the facility is provided for the periodic or continuous removal of the hydrogen gas from the vessel or container where the facility is the vent, pipe, pump or other means for removing gas from the vessel or container; the facility is provided for periodic or continuous addition of the metal carbonate mass into the vessel or the container and the facility is the pipe, slide, port, conveyor belt, or other means of adding a mass to a vessel or container; the facility is provided for the periodic or continuous addition of the water solution into the vessel or the container and the facility is the pipe, slide, port, pump, or other means; the facility is provided for the periodic or continuous removal of the metal hydroxide from the vessel or the container and the facility is the vent, port, pump, drain, or other means. The water solution is contained in industrial or municipal waste water or other non-natural water source. The gas mixture is contained in air or other naturally occurring gas mixture, or as contained in industrial or waste gas or other non-naturally occurring gas. Preferred Method: In the method of making metal hydroxide: the metal carbonate mass is insoluble or sparingly soluble in the water solution prior to the introduction of the electricity to the electrolysis cell.