Solubility of a substance is one the properties of chemical compounds. It is the amount of a substance that dissolves in a given solvent. (This because not all compounds dissolves in water, some dissolves in organic and inorganic compounds). It is a measure of the maximum amount of the solute that will dissolve in the solvent at equilibrium point or at saturation point.
Compounds have substances they dissolve in like ethanol is miscible with water while kerosene is immiscible in water unless a detergent is use as an emulsifier. Also to a degree it will still separate. Reason for this action is the difference in polarity as non polar solvents cannot dissolve on polar solvents. Therefore beyond equilibrium point of dissolution a super saturated solution can be obtained which is meta-stable. (This can be a pure solution or mixture).
As discussed earlier, insolubility ifs a function of polarity of the solvents involved; the process a substance dissolves in a solvent is called dissolution. If compounds of the same polarity come in contact, the unlike ions forms an inter-molecular forces such as hydrogen bonds. This case is seen in dissolution of sodium chloride in water; the ionic lattices separate and are solvated with water molecules. see this
Solubility of liquids in liquids
Liquids mix in proportion with each other therefore, they have mutual solubility and are said to be miscible. Example is the mixture of gasoline with two cycle motor oil. The implication of polarity difference in like substances results to inter-molecular forces that lead to high boiling points of mixtures. This is because the dipole- dipole moments between the molecules are very high.
There are cases of partial solubility; the case of bromine and water. The mutual solubility is partially immiscible. Here, bromine is considered a non polar substance, and the partial solubility gives layers of two liquids involved. This is seen in the deep red color of bromine in water and partially clear water at the lower side of the vessel. chemical equilibrium
Solid solution in liquids
This part is explained by the dependence of solubility on temperature. The increase in temperature increases solubility. But the case of cerium sulfate is an objection to this law. it is on this dependence in temperature that super saturation is possible. It is worthy of note that some compounds dissolves sparingly at high temperatures; in this case decantation is carried out.
The graph below shows the solubility of some compounds;
Factors affecting solubility
The polarity of substance plays major role in solubility; as substance with the same polarity dissolves in each other.
Basically, the solubility of substances increases with increase in temperature. Here stirring of the dissolving mixture is encouraged. Stirring the mixture does not affect solubility but helps in speeding up the dissolution of the mixture.
The size of the molecules of compounds affects solubility. Smaller molecules cannot surround larger molecules.