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Saponification

Summary

Olive oil is saponified using a sodium hydroxide saturated methanol solution. The formation of suds in water is demonstrated with the resulting soap.

Hazards

The solution of NaOH in methanol is caustic.

Chemicals and Solutions

  • 30 mL of saturated NaOH in methanol (20g NaOH/30 mL MeOH)
  • Olive Oil

Materials

  • Stir rod
  • Beaker, 150mL
  • Graduated cylinder, 10 mL
  • Stoppered test tube with water

Procedure

  1. Put 6 mL of olive oil and 30 mL of saturated sodium hydroxide in methanol in a beaker.
  2. Add a stirring bar and stir. Soap forms.
  3. Shake some of the homemade soap with water and suds will form.

Discussion

Saponification is the alkaline hydrolysis of glyceryl trialkanoates to form glycerol and a mixture of salts of long chain carboxylic acids. These salts of long chain carboxylic acids are soaps.

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