What are Colloids?

Colloids are mixtures of two substances, where one is dispersed in the other in the form of small particles ranging from 0.001 to 1 micrometer in diameter. A colloid can consist of a solid, a liquid, or a gas dispersed evenly in a medium of another substance. The colloid maintains a separate physical state even though it is combined with another substance. Examples of colloids include fog, smoke, and even whipped cream.

Types of Colloids

Colloids can be categorized into two main types: lyophilic and lyophobic colloids. Lyophilic colloids, also known as emulsions, are formed when two different substances such as water and oil get attracted to each other, forming a homogeneous mixture with particles that move freely. An example of a lyophilic colloid is milk. Lyophobic colloids on the other hand are formed when two materials are not attracted to each other and when the particles have a negative charge. A familiar example is fog.

Characteristics of Colloids

Colloids have some unique characteristics, which makes them different from mixtures of other substances. First, colloids have relatively large particles that are too small to settle out of the mixture. This is why colloids have a homogenous appearance when observed with the naked eye. Secondly, colloids have a stable form and resist separation by sedimentation, filtration, or heating. Lastly, colloids can be viewed as a colloidal solution when subjected to light, which separates the colloid particles to form light and dark bands.

In conclusion, colloids are a type of mixture between two substances where one is dispersed in the other. They can be classified into two types- lyophilic or lyophobic- and have unique characteristics such as their large particles and stable form.