Question

Why does sodium octadecanoate waste soap during washing?

a) It enhances the cleaning power of soap.

b) It reacts with water to form a harmful byproduct.

c) It reduces the foaming ability of soap.

d) It accelerates the degradation of soap molecules.

Answer 1

Sodium octadecanoate, also known as sodium stearate, is a common ingredient in soap. It acts as a surfactant, meaning it helps to reduce the surface tension between water and dirt, which allows the soap to more effectively remove dirt and oils from surfaces. However, when used with hard water that contains calcium and magnesium salts, the sodium stearate can react with these divalent cations to form insoluble compounds, resulting in a decrease in the effectiveness of the soap.

Step-by-step explanation:

Sodium octadecanoate, also known as sodium stearate, is a common ingredient in soap. It acts as a surfactant, meaning it helps to reduce the surface tension between water and dirt, which allows the soap to more effectively remove dirt and oils from surfaces. However, when used with hard water that contains calcium and magnesium salts, the sodium stearate can react with these divalent cations to form insoluble compounds, resulting in a decrease in the effectiveness of the soap. This is why soap can waste during washing.