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Name: Laila
Status: educator
Grade: 9-12
Location: N/A
Country: N/A
Date: July 2007

Question:
While preparing soap in lab ethanol is added. What is the role of ethanol in soap?



Replies:
Laila,

I am assuming this is the soap preparation process that uses a fatty acid oil and sodium hydroxide in water. Since the oil and water do not mix, some solvent (the ethanol) that is able to dissolve partially in both the oil and the water helps to facilitate the reaction of sodium hydroxide with the fatty acid (to produce the fatty acid salt - soap, and water). The ethanol essentially allows better contact between the oil and the water.

Greg (Roberto Gregorius)


Ethanol is a wide spectrum anti-microbial agent. It is add to liquid (not solid) soaps to function as a germicide. It would be insoluble in solid soaps. I am not aware of the test data that shows its efficacy under various use conditions.

Vince Calder



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