As we all know that Acids and Bases are some of the basic or fundamental knowledge/ideas you need to know in Chemistry. But multiple interpretations, laws and concepts were introduced by different chemists throughout the course of time.
So in this article, I will be paying tribute to one of the earliest modern day establishment of the idea regarding acid and base reactions. Yes, from the title you can think that this article will be about ARRHENIUS acids and bases.
The first modern definition of acids and bases was devised by Svante Arrhenius, a Nobel Prize Winner for Chemistry. The Arrhenius definition of acids and bases is one of the oldest theories established.
It can be established based from Arrhenius himself that an Arrhenius acid is a substance that dissociates in water to form hydrogen ions (H) which generally increases the concentration of H+ ions in an aqueous solution while an Arrhenius base is a substance that dissociates in water to form hydroxide (OH−) ions which results to an increase in the concentration of OH− ions in an aqueous solution.
The Arrhenius concept is described as the formation of a water molecule from a proton and hydroxide ion. This leads to the definition that in Arrhenius acid–base reactions, a salt and water are formed from the reaction between an acid and a base. The acid-base neutralization reaction can be put into a word equation like the one below.
acid + base → salt + water
ARRHENIUS ACIDS
An Arrhenius acid causes the protonation or the creation of the hydronium (H3O+) ion in water. Moreover, in order for a chemical to qualify as an Arrhenius acid, upon the introduction to water, the chemical must cause an increase in the hydronium concentration or a decrease in the hydroxide concentration both of which are in aqueous form. This can be seen from the chemical reaction below.
It can be inferred that in this reaction nitric acid (HNO3) disassociates into hydrogen (H+) and nitrate (NO3-) ions when dissolved in water. This means that there is the production of a hydronium ion from the decomposition of reactant, HNO3.
ARRHENIUS BASES
On the other hand, to qualify as an Arrhenius base, upon the introduction to water, the chemical must either cause a decrease in the aqueous hydronium concentration, or an increase in the aqueous hydroxide concentration. This can be seen from the reaction below.
In the reaction above, lithium hydroxide (LiOH) dissociates into lithium (Li+) and hydroxide (OH-) ions when dissolved in water. This means that there is a formation of hydroxide ion which coincides with the Arrhenius definition.
Thank you! And I hope I have educated you with the adequate ideas regarding Arrhenius acids and bases!
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