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Explain how industrial production of sodium hydroxide is carried out by Castner-Kellner cell ? |
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Answer» Solution :Sodium hydroxide is generally prepared commercially by the electrolysis of sodium chloride in Castner-Kellner cell. A brine solution is electrolysed using a MERCURY cathode and a carbon anode. Sodium metal discharged at the cathode combines with mercury to form sodium amalgam. Chlorine gas is evolved at the anode. Cathode : `Na^(+)+e^(-) overset(Hg)to Na` - amalgam Anode : `CL^(-) to (1)/(2)Cl_(2)+e^(-)` The amalgam is TREATED with water to give sodium hydroxide and hydrogen gas. 2Na-amalgam `+2H_(2)O to 2NaOH +2Hg+H_(2)` PROPERTIES : Sodium hydroxide is a white, translucent solid. It melts at 591K. It is readily soluble in water to give a strong alkaline solution. CRYSTALS of sodium hydroxide are deliquescent. The sodium hydroxide solution at the surface reacts with the `CO_(2)`in the atmosphere to form `Na_(2)CO_(3)`. |
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