Solution Definition

What Is a Solution in Chemistry?

liquids in beakers
A chemical solution is homogeneous, so it has the same appearance and composition throughout. Heinrich van den Berg/Getty Images

A solution is a homogeneous mixture of two or more substances. A solution may exist in any phase.

A solution consists of a solute and a solvent. The solute is the substance that is dissolved in the solvent. The amount of solute that can be dissolved in solvent is called its solubility. For example, in a saline solution, salt is the solute dissolved in water as the solvent. For solutions with components in the same phase, the substances present in lower concentration are solutes, while the substance present in highest abundance is the solvent.

Using air as an example, oxygen and carbon dioxide gases are solutes, while nitrogen gas is the solvent.

Characteristics of a Solution

A chemical solution exhibits several properties:

  • A solution consists of a homogeneous mixture.
  • A solution is composed of one phase (e.g., solid, liquid, gas).
  • Particles in a solution are not visible to the naked eye.
  • A solution does not scatter a light beam.
  • Components of a solution cannot be separated using simple mechanical filtration.

Solution Examples

Any two substances which can be evenly mixed may form a solution. Even though materials of different phases may combine to form a solution, the end result always exists of a single phase.

An example of a solid solution is brass. An example of a liquid solution is aqueous hydrochloric acid (HCl in water). An example of a gaseous solution is air.

Solution TypeExample
gas-gasair
gas-liquidcarbon dioxide in soda
gas-solidhydrogen gas in palladium metal
liquid-liquidgasoline
solid-liquidsugar in water
liquid-solidmercury dental amalgam
solid-solidsterling silver