Preparation of Soap in a lab.

Asked by Tejkalyani | 18th Jun, 2008, 06:30: PM

Expert Answer:

Soap is produced in lab by sponification process.Saponification is commonly used to refer to the reaction of a metallic alkali (base) with a fat or oil to form soap. Saponifiable substances are those that can be converted into soap.

CH2-OOC-R - CH-OOC-R - CH2-OOC-R (fat) + 3 NaOH ( or KOH)

both heated →

CH2-OH -CH-OH - CH2-OH (glycerol) + 3 R-CO2-Na (soap)
where R=(CH2)14CH3 in the example (right)

Sodium hydroxide (NaOH) is a caustic base. If NaOH is used a hard soap is formed, whereas when potassium hydroxide (KOH) is used, a soft soap is formed. Vegetable oils and animal fats are fatty esters in the form of triglycerides. The alkali breaks the ester bond and releases the fatty acid and glycerol. If necessary, soaps may be precipitated by salting it out with saturated sodium

Answered by  | 21st Jun, 2008, 05:24: PM

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