Utah Esthetician State Board Practice Exam

What is a common characteristic of all surfactants?

1. They are hydrophobic only

2. They lower surface tension between liquids

3. They are exclusively natural

4. They have a high viscosity

The correct answer is: They lower surface tension between liquids

Surfactants, or surface-active agents, are unique in their ability to lower the surface tension between two liquids, or between a liquid and a solid. This characteristic is vital for their function in various applications, such as cleansing, emulsifying, and foaming. By reducing surface tension, surfactants enable the mixing of substances that would normally remain separate, such as oil and water, which is crucial for effective cleaning and product formulation in the field of esthetics. The other options do not accurately define surfactants. Being hydrophobic only does not encompass the full spectrum of surfactant properties, as many surfactants possess both hydrophilic (water-attracting) and hydrophobic (water-repelling) characteristics simultaneously. While some surfactants are derived from natural sources, not all are exclusively natural; many synthetic surfactants are widely used. Additionally, surfactants do not inherently have a high viscosity, as viscosity can vary significantly among different types of surfactants depending on their formulation and concentration.