Which type of substances typically will not mix with water?

Hydrocarbons are organic compounds primarily composed of hydrogen and carbon atoms. Their chemical structure leads to hydrophobic properties, meaning they do not interact well with water. When hydrocarbons come into contact with water, they tend to separate rather than dissolve or mix. This characteristic makes them significantly different from substances like salts, acids, and alcohols, which can dissolve in water due to their ionic or polar nature.

Salts, for example, dissociate in water to form ions, which is essential for various chemical reactions and biological processes. Acids also mix with water, often releasing hydrogen ions and altering the pH of the solution. Alcohols, while they have hydrocarbon chains, possess hydroxyl groups (-OH) that allow for hydrogen bonding with water molecules, making them soluble.

Given this understanding, hydrocarbons stand out as substances that typically will not mix with water, a behavior crucial for applications in fire behavior and safety management. This characteristic informs procedures for managing spills and ignitions involving hydrocarbon-based materials.