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Chlor-Alkali Process

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Explain the Chlor-Alkali Process

When electricity is passed through an aqueous solution of sodium chloride (called brine), it decomposes to form sodium hydroxide. The process is called the chlor-alkali process.

This process is taken place by electrolysis of aqueous chloride.

The chemical equation of this process is as follow:

2NaCl(aq) + 2H₂O (1) →2NaOH(aq) + Cl₂ (g) + H₂(g)

When electricity is passed through an aqueous solution of sodium chloride (called brine), Chlorine gas is given off at the anode, and hydrogen gas at the cathode. Sodium hydroxide solution is formed near the cathode.

Products of Chlor-Alkali Process

  1. Sodium Hydroxide
  2. Chlorine Gas
  3. Hydrogen Gas

Production of Hydrochloric Acid

Chlorine and hydrogen are the major products of the chlor-alkali process, which are used to make hydrochloric acid. Hydrochloric acid is a common chemical product used in the production of medications, cosmetics, and ammonium chloride, as well as for steel cleaning.

Production of Bleaching powder: Bleaching powder is produced by the action of chlorine on dry slaked lime [Ca (OH)2]. The chlor-alkali process produces chlorine gas by electrolysis of aqueous sodium chloride.

The chemical equation of this process is: Ca (OH)₂+ Cl₂ → CaOCl2 + H2O