Otis watches a cooking show on making mayonnaise. The chef dissolves salt and sugar in vinegar. She mixes in an egg yolk, and then mixes in oil until the ingredients are completely blended together. The chef says that it’s great on sandwiches and that it can be stored without separating. Which best describes the purpose of the egg yolk in the recipe?

Answer/Explanation:

This is an emulsion. Emulsions are homogenous mixtures of two or more liquids that are normally not mixable. They need another substance in order for it to mix. In mayonnaise the yolk is needed to mix the water and oils. Water and oil are destined to separate from each other because of the difference in densities. Adding the yolk causes it to be a better balanced mixture that will keep it together.