9.4: Solutions - Homogeneous Mixtures

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Learning Objectives

Learn terminology involving solutions.

Attractive forces are also important for the formation of solutions. We will discuss why attractive forces are important in one of the subsections of this chapter, but first we will define a few terms that are important for solutions.

The major component of a solution is called the solvent. The minor component of a solution is called the solute. By major and minor we mean whichever component has the greater or lesser presence by mass or by moles. Sometimes this becomes confusing, especially with substances with very different molar masses. However, here we will confine the discussion to solutions for which the major component and the minor component are obvious.

Solutions exist for every possible phase of the solute and the solvent. Salt water, for example, is a solution of solid \(\ce{NaCl}\) in liquid water, while air is a solution of a gaseous solute (O₂) in a gaseous solvent (N₂). In all cases, however, the overall phase of the solution is the same phase as the solvent. Table \(\PageIndex{1}\) lists some common types of solutions, with examples of each.

Table \(\PageIndex{1}\): Types of Solutions
Solvent Phase	Solute Phase	Example
gas	gas	air
liquid	gas	carbonated beverages
liquid	liquid	ethanol (C₂H₅OH) in H₂O (alcoholic beverages)
liquid	solid	salt water
solid	gas	H₂ gas absorbed by Pd metal
solid	liquid	Hg(ℓ) in dental fillings
solid	solid	steel alloys

Figure \(\PageIndex{1}\): Making a saline water solution by dissolving table salt (NaCl) in water. The salt is the solute and the water the solvent. (CC-BY-SA 3.0; Chris 73).

Example \(\PageIndex{1}\): Sugar and Water

A solution is made by dissolving 1.00 g of sucrose (\(\ce{C12H22O11}\)) in 100.0 g of liquid water. Identify the solvent and solute in the resulting solution.

Solution

Either by mass or by moles, the obvious minor component is sucrose, so it is the solute. Water—the majority component—is the solvent. The fact that the resulting solution is the same phase as water also suggests that water is the solvent.

Exercise \(\PageIndex{1}\)

A solution is made by dissolving 3.33 g of \(\ce{HCl(g)}\) in 40.0 g of liquid methyl alcohol (\(\ce{CH3OH}\)). Identify the solvent and solute in the resulting solution.

Answer: solute: HCl(g); solvent: CH₃OH

Summary

Solutions are composed of a solvent (major component) and a solute (minor component).

Contributions & Attributions

This page was constructed from content via the following contributor(s) and edited (topically or extensively) by the LibreTexts development team to meet platform style, presentation, and quality:

Marisa Alviar-Agnew (Sacramento City College)
Henry Agnew (UC Davis)