What term describes substances that cannot mix with one another?

The term that describes substances that cannot mix with one another is "immiscible." This term is particularly important in chemistry and cosmetology for understanding the behavior of liquids. When two substances are immiscible, they will not form a homogeneous mixture, meaning that they will separate and remain distinct when combined. A common example of immiscible substances is oil and water, where oil floats on top due to its inability to dissolve or integrate with water.

Understanding this concept is crucial in chemical texturizing processes, as it helps in predicting how various products will interact when applied to hair. For instance, when mixing certain products for chemical treatments, knowing whether the components are miscible or immiscible can inform the effectiveness and stability of the mixtures used in hair services.

The other terms do not accurately define this concept. "Miscible" refers to substances that can mix uniformly, "soluble" relates to a substance's ability to dissolve in a solvent, and "coupled" typically describes elements that are linked or paired together rather than their ability to mix.