Which of the following best describes the behavior of azeotropes when subjected to changes in temperature?

• A. They separate into individual components
• B. Their composition changes
• C. They maintain a constant composition
• D. They freeze at lower temperatures

Answer: (C)

Azeotropes are unique mixtures of two or more components that behave as a single substance when changes in temperature occur. When the temperature of an azeotropic mixture is altered, it will not change in composition; instead, it will distill at a constant boiling point and maintain that same ratio of components throughout the process. This characteristic is key to understanding the nature of azeotropes, as they have specific boiling and condensation points that differentiate them from regular mixtures.

For instance, if you were to heat an azeotropic solution, the vapors produced would retain the same proportion of the components as found in the original liquid phase. This is significant during distillation processes as it limits the effectiveness of separation techniques for azeotropic mixtures, meaning that standard distillation cannot achieve complete separation of the components.

The other options do not accurately describe the nature of azeotropes. They do not separate into individual components under temperature changes, their composition does not vary, and there is no distinct freezing point conversion associated with lower temperatures, which applies differently to pure substances rather than azeotropic mixtures.