A substance which is dissolved in a solution is called a solute. In fluid solutions, the amount of solvent present is greater than the amount of solute. One best example of solute in our day to day activity is salt and water. Salt dissolves in water and therefore, salt is the solute.
What is Solute?
A homogeneous mixture composed of two or more substances, in which a mixture, a solute is a substance dissolved in another substance known as a solvent. The concentration of a solute in a solution is a measure of how much of that solute is dissolved in the solvent, with regard to how much solvent is present like salt.
Characteristics of Solute
- A solution is a homogeneous mixture of two or more substances.
- The particles of solute in a solution cannot be seen by the naked eye.
- A solution does not allow beams of light to scatter.
- A solution is stable.
- The solute from a solution cannot be separated by filtration (or mechanically).
- It is composed of only one phase.
Types of Solute
Homogeneous means that the components of the mixture form a single phase. Heterogeneous means that the components of the mixture are of different phase.
The properties of the mixture including concentration, temperature, and density can be uniformly distributed through the volume but only in the absence of diffusion phenomena or after their completion. The major types of solute are:
If a solvent is a gas, then only gases are dissolved under a given set of conditions. An example of a gaseous solution is air such as oxygen and other gases dissolved in nitrogen.
If the solvent is a liquid, then almost, liquids, and solids can be dissolved. Here are some examples:
- Gas in liquid
- Oxygen in water
- Carbon dioxide in water
- Liquid in liquid
- The mixing of two or more substances of the same chemistry but different concentrations to form a constant.
- Alcoholic beverages are basically solutions of ethanol in water.
- Solid in liquid:
- Sucrose (sugar) in water
- Sodium chloride (NaCl) (salt) in water.
If the solvent is solid, then gases, liquids and solids can be dissolved.
- Gas in solids
- Hydrogen dissolves rather well in metals, especially in palladium;
- Liquid in solid
- Mercury in gold, forming an amalgam
- Water in solid salt or sugar, forming moist solids
- Hexane in paraffin wax
- Solid in solid
- Steel, basically a solution of carbon atoms in a crystalline matrix of iron atoms.
- Alloys like bronze and many others.
- Polymers containing plasticizers.
The solute examples are listed below with the corresponding solution.
|Solutions||Corresponding solute in the solution|
|Brass alloy||Zinc in copper|
|Amalgam||Mercury in silver|
|Antifreeze in radiator||Ethylene glycol in water|
|Carbonated beverages||CO2 in water|
|Air in atmosphere||Many gases in nitrogen|
|Bronze||Tin dissolved in copper|
|Sugar water||Sugar dissolved in water|
|Alcoholic drinks||Alcohol dissolved in water|
|Saltwater||Salt dissolved in water|
Saturated and Unsaturated solution
When a solution dissolves solute as much as possible at a particular temperature, is called a saturated solution. In simple terms, it can also be defined as, at a given temperature when no more solute can dissolve itself in the solution, it is a saturated solution. When the quantity of solute is not as same as the saturation level but less than that, it is known as an unsaturated solution.