Lye from salt

Making lye at home using salt and electricity

Scientific name: Electrolysis of sodium chloride solution

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Safety

Wear lab gloves and eye protection.

Follow the safety instructions when dealing with electricity.

Always follow general safety recommendations. Please note that conducting chemistry experiments you must comply with the relevant legal procedures in your country.

Reaction formula

2 H2O + 2e → 2 OH- + H2

Cl- - 2e → 2 Cl2

Step-by-step instruction

  1. Pour some water into a beaker.
  2. Add salt (not iodized) to prepare a very concentrated sodium chloride solution.
  3. Secure two graphite electrodes connected to a power supply.
  4. Switch on the power supply. Electrolysis should gone on for several hours.
  5. Evaporate the obtained solution to precipitate sodium hydroxide.

Scientific background

Sodium is an active metal, and in order to reactivity series hydrogen produces on the cathode in the electrolysis process. Thus, water undergoes electrolysis on the cathode, hydrogen and OH- ions are formed.

Chlorine is produced on the anode. Because of this the experiment should be performed in a well-ventilated room.

As a result of the electrolysis process sodium hydroxide is formed in the solution. It may be precipitated with boiling down the solution.

Danger:
Coolness:
Difficulty:

Published on 09 September 2015

  • Fire
  • Heating with fire
  • Explosion
  • Poisoned gas
  • Organic
  • Electricity
  • Solution
  • Oxidation reduction
  • Color change
  • Precipitate
  • Gassing
  • Catalyst