Choose the best answer: A colloidal dispersion of one liquid
in another is called (a) a gel, (b) an emulsion, (c) a foam,
(d) an aerosol

Verified step by step guidance

1. Identify the key terms in the question: 'colloidal dispersion' and 'one liquid in another'.
2. Recall the definition of a colloid: a mixture where one substance is dispersed evenly throughout another.
3. Understand that when both substances in a colloid are liquids, it is specifically called an emulsion.
4. Review the options: (a) gel, (b) emulsion, (c) foam, (d) aerosol.
5. Recognize that an emulsion is the correct term for a colloidal dispersion of one liquid in another.

Key Concepts

Colloidal Dispersion

A colloidal dispersion is a mixture where tiny particles of one substance are evenly distributed throughout another substance. These particles are larger than molecules but too small to be seen with the naked eye. Colloids can exist in various forms, including solid, liquid, or gas, and their stability is influenced by factors such as particle size and charge.

Emulsion

An emulsion is a specific type of colloidal dispersion where one liquid is dispersed in another liquid with which it is usually immiscible, such as oil in water. Emulsions are stabilized by emulsifying agents that reduce the surface tension between the two liquids. Common examples include mayonnaise and salad dressings, which demonstrate how emulsions can be both stable and useful in culinary applications.

Types of Colloids

Colloids can be classified into various types based on the phases of the dispersed and continuous mediums. For instance, a gel is a solid dispersed in a liquid, a foam is a gas dispersed in a liquid, and an aerosol is a solid or liquid dispersed in a gas. Understanding these classifications helps in identifying the correct terminology and properties associated with different colloidal systems.