A neutralization reaction is a reaction in which an acid and a base react in an aqueous solution to produce a salt and water.
The Arrhenius definition of an acid is any compound that increases the amount of hydrogen ion (H+) in an aqueous solution. The chemical opposite of an acid is a base. The equivalent The Arrhenius definition of a base is any compound that increases the amount of hydroxide ion (OH−) in an aqueous solution.
The reaction of an acid and a base is called a neutralization reaction. Although acids and bases have their own unique chemistries, the acid and base cancel each other’s chemistry to produce a rather innocuous substance—water (with a pH of 7). In fact, the general reaction between an acid and a base is
acid + base → water + salt
where the term salt is generally used to define any ionic compound (soluble or insoluble) that is formed from a reaction between an acid and a base.
In a neutralization reaction, acids (proton donors) produce hydrogen ions (H+) when added to water due to their dissociation. Bases (proton acceptors) in solution will produce hydroxide ions (OH–). When H+ ions react with OH– ions, it produces water (H2O). This results in a neutral solution that contains salt and water with a pH of 7.
For example, take a look at the reaction of hydrochloric acid (HCl) with sodium hydroxide (NaOH). This will produce the salt sodium chloride (NaCl) and water (H2O), a neutral solution with a pH of 7.
Key Points
• The Arrhenius definition of an acid is a substance that increases the amount of H+ in an aqueous solution.
• The Arrhenius definition of a base is a substance that increases the amount of OH− in an aqueous solution.
• Neutralization is the reaction of an acid (proton donor) and a base (proton acceptor), which forms water and a salt.
• The product of a neutralization reaction has a pH of 7.
Key Terms
Acid: A substance that produces protons (H+ ions) when dissolved in water.
Base: A substance that produces hydroxide ions (OH-) ions when dissolved in water.
Arrhenious acid: A substance that dissociates in water to form hydrogen ions or protons (H+).
Arrhenious base: A substance that dissociates in water to form hydroxide ions, OH–).
Neutralization reaction: When an acid and a base react to form water and a salt and involves the combination of H+ ions and OH- ions to generate water. The neutralization of a strong acid and strong base has a pH equal to 7.
pH: A figure expressing the acidity or alkalinity of a solution on a logarithmic scale on which 7 is neutral, lower values are more acid and higher values more alkaline.