Why is mayonnaise a heterogeneous mixture?

Mayonnaise is considered a heterogeneous mixture because it consists of multiple phases that are not uniformly distributed throughout the mixture. It is an emulsion of oil, vinegar, and egg yolk. The oil and vinegar are immiscible liquids, meaning they do not mix together to form a homogeneous solution. Instead, the oil droplets are suspended within the vinegar and egg yolk mixture, creating a heterogeneous mixture.

When you mix mayonnaise, you can observe the different components and their distinct properties. The oil droplets appear as tiny globules dispersed throughout the mixture, giving mayonnaise its characteristic creamy texture. The vinegar and egg yolk form the continuous phase, holding the oil droplets together. This mixture can exhibit phase separation over time, with the oil droplets rising to the surface due to their lower density compared to the vinegar and egg yolk phase.

Therefore, mayonnaise is classified as a heterogeneous mixture because of its non-uniform composition, where the different components retain their individual properties and are not completely integrated at the molecular level.