In the ethanol emulsion test for fats, what observation indicates fat is present?

• A. Clear water
• B. White and opaque emulsion
• C. Cloudy mixture
• D. Yellow layer

Answer: (B)

Fats don’t dissolve in water, but they do dissolve in ethanol. In the ethanol emulsion test, fat is first extracted into ethanol, and when you add water, the dissolved fat forms tiny droplets that stay dispersed, creating a milky, white, opaque emulsion. That milky appearance is the clear sign that fat is present. If there were no fat, the mixture would remain clear because there would be no dispersed fat droplets to scatter light. A yellow layer or just general cloudiness isn’t the specific result of this test.