Definition of solubility
Solubility is defined as the maximum amount of one substance that can be dissolved in another. This is the maximum amount of solute that can be dissolved in an equilibrium solvent , which produces a saturated solution. When certain conditions are met, the additional solute can be dissolved beyond the equilibrium solubility point, which produces a supersaturated solution. Beyond saturation or supersaturation, the addition of more solute does not increase the concentration of the solution.
Instead, the excess solute begins to precipitate out of the solution. solubility in chemistry
The dissolution process is called dissolution . Solubility is not the same property of matter as the speed of the solution, which describes the speed with which a solute dissolves in a solvent. Solubility is also not the same as the ability of one substance to dissolve another as a result of a chemical reaction. For example, metallic zinc “dissolves” in hydrochloric acid through a displacement reaction which dissolves zinc ions and releases hydrogen gas. Zinc ions are soluble in acid. The reaction does not depend on the solubility of the zinc.
In familiar cases, a solute is a solid (for example, sugar, salt) and a solvent is a liquid (for example, water, chloroform), but the solute or solvent can be a gas, a liquid or solid. The solvent can be a pure substance or a mixture . solubility in chemistry
The term insoluble implies that a solute is sparingly soluble in a solvent. solubility in chemistry
In very rare cases, is it true, no solute dissolves. Generally, an insoluble solute still dissolves a little. Although there is no strict limit defining a substance as insoluble, it is common to apply a threshold where a solute is insoluble is less than 0.1 gram dissolved per 100 milliliters of solvent. solubility in chemistry
Miscibility and solubility
If a substance is soluble in all proportions in a specific solvent, it is called miscible or has the property called miscibility . For example, ethanol and water are completely miscible with each other. On the other hand, oil and water do not mix and do not dissolve into each other. Oil and water are considered immiscible . solubility in chemistry
Solubility in action
The dissolution of a solute depends on the types of chemical bonds in the solute and the solvent. For example, when ethanol dissolves in water, it retains its molecular identity as ethanol, but new hydrogen bonds are formed between ethanol and water molecules. For this reason, mixing ethanol and water produces a solution with a volume lower than that which you would obtain by adding the starting volumes of ethanol and water.
When sodium chloride (NaCl) or another ionic compound dissolves in water, the compound dissociates into its ions. The ions become solvated or surrounded by a layer of water molecules. solubility in chemistry
Solubility implies a dynamic equilibrium, involving opposite processes of precipitation and dissolution. Balance is achieved when these processes occur at a constant rate.
Solubility units solubility in chemistry
Tables and solubility tables indicate the solubility of various compounds, solvents, temperature and other conditions.
IUPAC defines solubility in terms of the proportion of solute relative to the solvent. Allowable concentration units include molarity, molarity, mass per volume, molar ratio, mole fraction, etc. solubility in chemistry
Factors Affecting Solubility
Solubility can be influenced by the presence of other chemical species in a solution, the phases of the solute and the solvent, the temperature, the pressure, the particle size of the solute and the polarity. solubility in chemistry
Examples of Solubility
The solubility is the property of each substance, whether gaseous, liquid or solid, which tells how much power will mix together to form a solution . A solution is a mixture between two or more components and that will have characteristics according to the amounts of each of them.
For there to be a two-component solution, these can be:
- A gas with another gas
- A liquid with a gas
- A solid with a gas
- A gas with a liquid
- A liquid with another liquid
- A solid with a liquid
- A gas with a solid
- A liquid with a solid
- One solid with another solid
The component that is in greater quantity is the solvent , and the one that is added to it is going to be the solute . The best-known and best-managed solutions are those that have a liquid solvent , and solutes that can be gas, liquid, or solid.
Solubility and solutions
According to the physical and chemical nature of the substances, they will have the ability to mix with others and achieve a homogeneous mixture , that is, in which only one phase is detected, or a heterogeneous one, in which two or more are seen. .
The solutions will be of three types depending on the amount of solute that has been added and its solubility:
- Dilute solutions
- Saturated solutions
- Supersaturated solutions
The diluted solutions are those that have little solute, and which may still receive more of this, leaving the homogenous mixture.
The saturated solutions are those which already have as much solute can dissolve. If more solute is added, it will be dispersed and visible, and the mixture will no longer be homogeneous.
The supersaturated solutions are those that have so much solute that it is already settling, as it cannot be integrated into the solution. solubility in chemistry
Factors modifying solubility
Coffee dissolves best in hot water. solubility in chemistry
Solubility, which is the ability of a solute to be dissolved in the solvent, will be modified according to a series of factors:
- The chemical character of the components
- The quantity of the components
- The pressure to which the solution is subjected
- The temperature at which the solution is
The chemical character of the components has a lot to do with it. For example, water and ethyl alcohol are chemically similar, so that between them they can dissolve without measure, always resulting in a homogeneous mixture. The case between water and oil is different. The latter has organic chemical structures that do not go along with water. solubility in chemistry
The quantity of components has a bearing on chemical character. For example, it has already been mentioned that water and alcohol will always be able to dissolve in all quantities with each other; on the other hand, water and ethyl ether have limited solubilities with each other. Ether can only dissolve a quantity of water as solute, and water can only dissolve a quantity of ether.
The pressure to which the solution is subjected affects in the following way: if the pressure is high , the particles will tend to remain more united, so the solubility will increase . On the other hand, if the pressure is low or vacuum , the particles will tend to be freer and more dispersed, so the solubility will decrease . solubility in chemistry
The temperature to which the solution is subjected affects the solubility in the following way: if the components absorb heat when they are mixed, the solubility will increase if we raise the temperature; that is, we are going to favor it. On the other hand, if the components release heat when they are mixed and we surround them with cold , we will motivate the solubility to increase .
Examples of solubility
The water H 2 O can dissolve an amount of sugar (or sucrose C 12 H 22 O 11 ). If the mixture is heated, it will be possible to continue adding sugar without the solution being oversaturated, also having a homogeneous mixture. solubility in chemistry
The water H 2 O can dissolve a quantity of table salt (sodium chloride NaCl). If the mixture is heated, it will be possible to continue adding salt, without the solution reaching supersaturation, also having a homogeneous mixture.
The ethyl alcohol C 2 H 5 OH dissolved to the water H 2 O in all proportions (water is completely soluble in ethyl alcohol).
The water H 2 O dissolves the ethyl alcohol C 2 H 5 OH in all proportions (ethyl alcohol is totally soluble in water).
The water H 2 O and the liquid metal mercury Hg do not dissolve each other, the solubility of one in another does not occur. solubility in chemistry
The water H 2 O may contain dissolved the ethyl ether (C 2 H 5 ) 2 O in a small proportion. If this is exceeded, two phases will begin to appear, creating a heterogeneous mixture with the excess ether.
The ethyl ether (C 2 H 5 ) 2 O may contain dissolved the water H 2 O in a small proportion. If this is exceeded, two phases will begin to be seen, creating a heterogeneous mixture with the excess water. solubility in chemistry
The air is completely soluble in pure oxygen O 2 .
The chlorine gas Cl 2 is completely soluble in gas bromine Br 2 .
The hydrogen gas H 2 is soluble in the solid metal palladium Pd , giving a homogeneous solid solution.
The liquid benzene C 6 H 6 is soluble solid iodine I 2 , creating a homogeneous solid solution. solubility in chemistry
The gold metal Au and the platinum metal Pt are soluble in each other if they are smelted. It is in their liquid state that they will create a mixture that, when it becomes solid, will be homogeneous. solubility in chemistry
The gold metal Au and the palladium metal Pd are soluble in each other if they are melted. It is in their liquid state that they will create a mixture that, when it becomes solid, will be homogeneous. solubility in chemistry