SOLUTION AND TYPES OF SOLUTION

SOLUTION AND TYPES OF SOLUTION

Before knowing the solution, let’s understand some related terms. After that we will be able to understand solution and its types.

Homogeneous & Heterogeneous mixture- A mixture in which constituents are distributed uniformly, such as salt in water, is called homogeneous, whereas a mixture whose constituents are clearly separate from one another, such as sand in water, it is called heterogeneous.

Homogeneous means that the components of the mixture form a single phase. Heterogeneous means that the components of the mixture are of different phase.

Solubility- The ability of one compound to dissolve in another compound is called solubility. The solubility of liquids in liquids is generally less temperature-sensitive than that of solids or gases.

Solute- A substance that is dissolved in a solution is called a solute or in other words, one or more components present in the solution other than the solvent are called solutes.

Solvent- A solvent is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid or a gas.

Example- One best example in our day to day activity is salt and water. Salt dissolves in water and therefore, salt is the solute. Whereas, water that dissolves a solute (here salt) is a solvent.

Now, understanding these terms let’s see what is solution?

Solution

• In chemistry, a solution refers to homogeneous mixture of two or more substances.
• Here two substances are the solute and the solvent. The solute is present in smaller quantity; while, solvent is present comparatively in larger quantity.
• One important parameter of a solution is the concentration, which is a measure of the amount of solute in a given amount of solution or solvent.
• The term “aqueous solution” is used when one of the solvents is water.
• Non-aqueous solutions are when the liquid solvent involved is not water.

Characteristics

• 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 cause beams of light to scatter.
• The solute from a solution cannot be separated by filtration (or mechanically).
• It is composed of only one phase.

Types of solution

The properties of the mixture (such as concentration, temperature, and density) can be uniformly distributed through the volume but only in absence of diffusion phenomena or after their completion. The solution has the same physical state as the solvent.

Gaseous mixtures

• If the solvent is a gas, only gases (non-condensable) or vapors (condensable) are dissolved under a given set of conditions. An example of a gaseous solution is air (oxygen and other gases dissolved in nitrogen).
• The Brownian motion and the permanent molecular agitation of gas molecules guarantee the homogeneity of the gaseous systems.
• Non-condensable gases mixtures (e.g., air/CO2 or air/xenon) do not spontaneously demix, nor sediment, as distinctly stratified and separate gas layers as a function of their relative density.
• In case of condensable vapors, once the saturation vapor pressure at a given temperature is reached, vapor excess condenses into the liquid state.

Liquid solutions

• If the solvent is a liquid, then almost all gases, liquids, and solids can be dissolved.
• Examples: Gas in liquid- (Oxygen in water), Liquid in liquid- (Alcoholic beverages are basically solutions of ethanol in water), Solid in liquid-(Sucrose in water).

Solid solutions

• If the solvent is a solid, then gases, liquids, and solids can be dissolved.
• Gas in solids- (Hydrogen dissolves in metals), Liquid in solid- (Water in solid salt or sugar), Solid in solid- (Alloys like bronze and many others)

Types of solution based on Water as Solvent

1. Aqueous solutions: These solutions have water as the solvent. Examples are sugar in water, carbon dioxide in water, etc.
2. Non-Aqueous Solutions: These solutions have a liquid solvent that is not water. It could be ether, benzene, petrol, carbon tetrachloride etc. for example, sulfur in carbon.

Based on Amount of Solute Added

1. Unsaturated Solution: An unsaturated is one that can dissolve more solute at a definite temperature. Hence one can still add more solute to the solvent.
2. Saturated Solution: A solution is said to be saturated when we can’t add any more solute to the solvent. It means, solution can’t dissolve any more solute at a definite temperature.
3. Supersaturated Solution: In this type of solution, solute is present in an excess amount. This solute is dissolved forcefully by raising the temperature or pressure of the solution. The process of crystallization is used to crystal out in the bottom.

Based on Amount of Solvent Added

1. Concentrated Solution: A concentrated solution has large amounts of solute in the given solvent. Examples are orange juice, brine solution.
2. Dilute Solution: A dilute solution has a small amount of solute in a large amount of solvent. Examples include Salt solution, light colour tea.

Based on Concentration of Solute in Two Solutions

1. Isotonic Solution-A solution is isotonic when its effective solute concentration is the same as that of another solution. The solutions on either side of a cell membrane are isotonic if the concentration of solutes outside the cell is equal to the concentration of solutes inside the cell.
2. Hypertonic Solution-A hypertonic solution has a greater concentration of solutes than another solution. A solution outside of a cell is called hypertonic if it has a greater concentration of solutes than the cytosol inside the cell.
3. Hypotonic Solution- A hypotonic solution has a lower concentration of solutes than another solution. In biology, a solution outside of a cell is called hypotonic if it has a lower concentration of solutes relative to the cytosol.