Topic: Sodium Hydroxide


Sodium Hydroxide, also called Lye or Caustic Soda, is a caustic metalic base.

(My experience has been, if you are talking to Chemists, then call it Sodium Hydroxide. Else, call it Lye.)

Lye has a chemical symbol of NaOH.

Concentrated Sodium Hydroxide is a white transluscent Deliquescent solid.

Uses of Lye

Lye has been used in the making of Soap, by reacting lye and a Fat. (Although, for making soap, instead of using lye, one can also use Potash or Soda Ash.)

In its more pure or concentrated forms, lye is also use as a generic strong base.

Lye is also used in the production of Wood Pulp and Paper.


WARNING: In its pure form or more concentrated forms, lye is a very dangerous substance, and you should be extremely careful in its handling and storage!

Solid sodium hydroxide or solutions containing high concentrations of sodium hydroxide may cause Chemical Burns, permanent injury or scarring, and Blindness.

Any contact of lye with the skin should be washed thouroughly with (liquid) Water.

Making Lye

There are a number of known ways of making Lye.

Making Lye From Wood Ash

Lye has traditionally been made from Wood Ash.

Here are the steps on HOWTO create Lye from Wood or wood ash....

Step 1: Get Wood Ash. (If you don't have wood ash readily available, then get wood and burn it; and collect the ash created by burning the wood.)

Step 2: Put the wood ash in a pot with (liquid) Water in it. (Obviously don't put so much wood ash or water in there that you can't fit any of the other in there.)

Step 3: Scoop out any of the bits Charcoal that might be floating at the top of the pot (with the water and the wood ash in it).

Step 4: Bring the water (in the pot with the wood ash in it) to a boil.

Step 5: After it has boiled, let it cool off.

Step 6: After it has cooled off, strain the liquid with a Sieve (so that the big lumps are removed).

Step 7: After that, then strain the liquid through a piece of fine cloth.

The resulting liquid you get should be quite yellow, and if you strained it carefully, should be clear and look like pee.

This should have a pH of at least 10.

If you touch it, this liquid should feel soapy between your fingers.

Making Lye from Soda Ash and Lime

Sodium Hydroxide used to be mass produced by the treatment of Sodium Carbonate (also called Soda Ash or Washing Soda) with Calcium Oxide (also called Lime, Burnt Lime, or Quicklime).

Making Lye Via The Chloralkali Process

Alternatively, Lye can be made via the Chloralkali Process. Or in other words, lye can be made via the Electrolysis of Sodium Chloride.

Basically what this means is, take Water and put Sodium Chloride in it. (Remember, Sodium Chloride is Table Salt... which is also called Common Salt.) Then perform Electrolysis on it, while taking special measures to make sure the Chlorine that is created from this does not react with the Sodium Hydroxide -- the lye -- that is building up on the Cathode.

The following reaction, for this is as follows, which will produce Lye (Sodium Hydroxide) as well as Chlorine and Hydrogen....

  2Na+ + 2H2O + 2e- → H2 + 2NaOH

The Sodium Hydroxide -- the lye -- builds up on the Cathode.

NOTE, to produce the Sodium Hydroxide, it is necessary to prevent the Sodium Hydroxide from reacting with the Chlorine also being produced. This can be done in (at least) three different ways....

See Also
-- Mirza Charles Iliya Krempeaux