Which of the following describes a combination of two or more substances where the initial components are not mixable?

An emulsion is defined as a mixture of two immiscible liquids, where one liquid contains a dispersion of the other. In an emulsion, the substances are usually oil and water, which do not naturally mix. To form a stable emulsion, an emulsifier is often used, which helps to bind the two immiscible liquids together, creating a uniform mixture. Common examples of emulsions include mayonnaise and lotions.

A solution, on the other hand, involves a homogeneous mixture where one substance (the solute) is completely dissolved in another (the solvent), indicating they are fully mixable. A suspension refers to a mixture where solid particles are dispersed in a liquid but are not dissolved, often leading to the solid settling at the bottom over time. A mixture is a broad term that can describe any combination of substances but does not specifically pertain to the immiscibility characteristic required to define an emulsion.

Understanding emulsions is crucial in esthetics because many skincare products utilize emulsification to combine oils and water, ensuring the product has the right texture and effectiveness.