Sodium Hydroxide - Production

Essay by PaperNerd ContributorHigh School, 12th grade September 2001

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Task: Research and describe the production of a named chemical including safety precautions.

Sodium Hydroxide: Sodium Hydroxide, a white solid with a melting point of 318°C, is otherwise known as caustic soda or lye. The major industrial uses of sodium hydroxide are in the manufacture of chemicals, pulp and paper, aluminium, soaps and detergents. Sodium Hydroxide is also used in water treatment, food processing, flue-gas scrubbing, mining, glass making, textile processing and refining. The digestive effects of Sodium Hydroxide on organic materials is the main principle behind drain cleaners.

Chemical Production: Chlorine and sodium Hydroxide are both manufactured by the electrolysis of brine (aqueous sodium chloride) Electrolysis 2 Na+(aq) + 2 Cl¯(aq) + 2 H2O (l)>>> Cl2 (g) + H2 (g) + 2 Na+(aq) + 2 OH¯(aq) During electrolysis, chlorine is formed at the anode, whilst hydrogen and hydroxide ions are formed at the cathode i.e.

2Cl¯ >>> Cl2 + 2e¯ and 2H2O + 2e¯ >>> H2 + 2OH¯ The removal of chloride and hydrogen leaves sodium ions and hydroxide ions in solution. The sodium hydroxide is obtained by concentrating the electrolyte removed from the apparatus. The concentration occurs by evaporating off any excess water. In the manufacture of sodium hydroxide, the chlorine gas and hydrogen gas also produced are collected separately. The chlorine is commonly dried, compressed and liquefied. Although the hydrogen can be compressed and stored, the value of hydrogen is not sufficient to warrant this, the hydrogen is thus usually burned at the electrolysis plant to provide thermal energy.

Safety Precautions: Sodium Hydroxide in solution is extremely reactive. It reacts violently with numerous commonly encountered materials, generating enough heat to ignite nearby materials. Contact with several organic and inorganic materials may cause fire or an explosion. Because of its explosive...