Atbases are substances that when added to water have the characteristic of releasing as the only anion the hydroxide, oh-1. When in water, the bases suffer the phenomenon of dissociation, which is the release of ions in an aqueous medium. The amount of anions a given base will release is related to the base's ability to dissolve in water.
Thus, it is very important to know the solubility that the base presents in water to predict whether or not it can release many ions in water, that is, whether or not it can be a good electrolyte (substance capable of ionizing or dissociating). Knowledge about the solubility of bases often determines how it will be used or used. For example:
Sodium hydroxide (NaOH) cannot be used as an antacid because it is an extremely soluble base, which determines that it is a very strong base.
Aluminum hydroxide [Al(OH)3] can be used as an antacid because it is a practically insoluble base, which characterizes it as a weak base.
Note: The stronger the base, the greater its corrosion power. That's why we don't use a strong base as an antacid, so as not to damage the individual's digestive tract.
Base being dissolved in water
To determine the solubility of a base, it is enough to evaluate its chemical formula and compare it to the periodic table. The chemical element that accompanies the hydroxyl (OH) is who will determine the type of base we have in terms of solubility. Base classifications for solubility are:
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a) Soluble bases
Are the bases formed by chemical elements alkali metals (present in the family IA), but there is an exception to this rule, which is ammonium hydroxide (NH4OH). Examples of soluble bases:
LiOH (lithium hydroxide)
NaOH (Sodium hydroxide)
KOH (Potassium hydroxide)
b) Poorly soluble bases
Are the bases formed by chemical elements alkali metals earthy (present in the family IIA). Examples of poorly soluble bases:
Mr (OH)2 (strontium hydroxide) - used in the refinement of beet sugar.
Ca(OH)2 (Calcium hydroxide) - used in constructions.
Note: The bases formed by magnesium [MgOH)2] and by beryllium [Be (OH)2], which are alkali metals, have such low solubility that they are considered practically insoluble.
c) Practically insoluble bases
These are the bases that do not have elements of alkali metals or alkaline earth metals in their composition. Examples of practically insoluble bases.
Ni(OH)2 (Nickel hydroxide II) – present in batteries
Fe(OH)3 (Iron hydroxide III) - used as brown pigment
Cu(OH)2 (copper hydroxide II) - used as a fungicide
Note: Complete your study on the solubility of bases by learning to determine their strength in the text Strength or degree of dissociation from bases.
By Me. Diogo Lopes Dias
Would you like to reference this text in a school or academic work? Look:
DAYS, Diogo Lopes. "Solubility of bases"; Brazil School. Available in: https://brasilescola.uol.com.br/quimica/solubilidade-das-bases.htm. Accessed on June 28, 2021.
Base Nomenclature, Aqueous Solution, Ionic Dissociation, Cation, Anion, Sodium Hydroxide, Aluminum Hydroxide, Iron Hydroxide, Copper Hydroxide, Ferric Hydroxide, Calcium Hydroxide.
