A more permanent mixture of two immiscible substances is referred to as what?

The correct answer is emulsion. An emulsion is a stable combination of two immiscible liquids, meaning that they do not mix naturally, such as oil and water. In cosmetic and pharmaceutical formulations, emulsions are crucial because they allow for the blending of ingredients that would typically separate.

Emulsions are created using emulsifiers, which are substances that help stabilize the mixture by lowering the surface tension between the two immiscible liquids. They are commonly used in products like creams and lotions, where a smooth, uniform appearance is desired.

A suspension refers to a mixture where solid particles are dispersed in a liquid but may settle over time. While a suspension can also involve immiscible substances, it does not imply a stable combination. A solution represents a homogeneous mixture of solute and solvent, where one substance is completely dissolved in another, rather than two distinct phases. Lastly, a mixture is a general term that can apply to any combination of substances but doesn’t specify the nature of the combination, such as stability or phase separation. Therefore, emulsion is the most precise term for the scenario described.