General Properties of Solutions

Mixtures are substances that are composed of varying amounts of two or more types of molecules or atoms. Sand mixed with iron filings and lemonade are both examples of mixtures. Mixtures can be categorized into two types - heterogeneous and homogeneous.

In heterogeneous mixtures, the components are unevenly distributed; hence, they do not exhibit a uniform composition. 

In contrast, homogeneous mixtures do have a uniform composition. 

For example, lemonade is a homogeneous mixture of lemon juice, sucrose, and water. Each drop of lemonade tastes the same due to the uniform distribution of its ingredients.

A solution is a homogenous mixture of two main substances – the solute and the solvent.  The solvent is present in greater quantity than the solute. 

For example, in lemonade, water is the solvent, and lemon juice and sucrose are the solutes. 

In a solution, the solute and solvent can be in any state of matter: solid, liquid, or gas. The state of the solution is the same as the state of the solvent. The solution itself is a single “phase”, irrespective of the states of the solvent and solutes.

For example, soda is a liquid solution that contains gaseous carbon dioxide and solid sucrose dissolved in water.

When the solvent is water, the solution is called aqueous. Lemonade and soda are both examples of aqueous solutions. 

When forming a solution, the solute and the solvent do not chemically react with each other. Instead, the particles are simply redistributed by individual solvent particles surrounding the solute particles and interacting through attractive forces. In the case of an aqueous solution, the dissolving process is called hydration. 

In general, the interaction of a solute with any solvent is called solvation.