What is a mixture that lowers the value or purity called?

A mixture that lowers the value or purity of a substance is known as adulteration. This term specifically refers to the process of adding inferior substances to a pure material, which results in a product that is of lower quality or value. Adulteration can occur in various industries, such as food and pharmaceuticals, where the integrity of the product is compromised by the introduction of lower-quality ingredients or additives.

Understanding this concept is important because it highlights how the purity of products can be affected and emphasizes the need for quality control measures in manufacturing and production processes. This term is distinct from others in the options: impurities denote foreign substances present, alloys refer to a mixture of metals that usually enhance properties rather than lower them, and compromise implies a settlement or middle ground, rather than a decrease in quality. Therefore, adulteration is the most accurate term for a mixture that degrades value or purity.