Electrolysis of water to produce gases

• Hydrogen gas is mainly produced using electrolysis of water
• In Zimbabwe this is done at the Sable Chemicals plant in Kwekwe
• Water is drawn from the Sebakwe River
• Electricity is taken from the ZESA grid and Sable has its own substation
• Pure water does not conduct electiricty very well as a result
• Potassium hydroxide (an alkali) or sulphuric acid is added to the water to improve its conductivity
• Carbon electrodes are used to carry current into and out of the electrolyte
• The size/chemical composition do not change during the process unlike in electroplating
• During the process water is broken into the elements
• Hydrogen and Oxygen
• The hydrogen comes from the cathode (negative) and
• The oxygen comes from the anode (positive)
• The Hydrogen and Oyxgen are produced in a ratio of 2:1
• The oxygen is then carried in pipes to ZISCO where it is used in the manufacture of steel
• The hydrogen is used in the manufacture of ammonia at Sable industries and the manufacture of margarine

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