The reason that acid-base reactions are so important is that many of the things you come into contact with on a daily basis are either acids or bases. Most fruits are acids, as are carbonated beverages, tea, and battery acid. Common household bases include baking soda, ammonia, soap, and antacids.
What are acids and bases?
There are not one but three common definitions used to describe acids and bases:
1. Arrhenius acids and bases
2. Brønsted-Lowry acids and bases
3. Lewis acids and bases.
These three definitions are roughly equivalent.
Arrhenius Acids and Bases
Way back in the late 1800s, Svante Arrhenius came up with definitions of acids and bases while working on kinetics problems.
According to Arrhenius, acids are compounds that break up in water to give off hydronium (H+) ions. A common example of an Arrhenius acid is hydrochloric acid (HCl):
HCl ⇔ H+ + Cl-
The formulas for acids usually start with hydrogen, though organic acids are a notable exception.
Arrhenius bases are defined as compounds that cause the formation of the hydroxide ion when placed in water. One example of an Arrhenius base is sodium hydroxide (NaOH):
NaOH ⇔ Na+ + OH-
Bases typically have "OH" in their formulas, though there are exceptions. For example, ammonia (NH3) doesn't contain hydroxide ions but forms them when it reacts with water:
NH3 + H2O ⇔ NH4+ + OH-
Svante arrhenius
Bronsted-lowry Acids and Bases
In the early 1900s, an alternate definition for acids and bases was proposed by Johannes Brønsted and Thomas Lowry to account for the fact that ammonia can neutralize the acidity of HCl even if water isn't present. This phenomenon showed them that ammonia is a base, even when there isn't water around to form hydroxide ions.
A Brønsted-Lowry acid is defined as a compound that gives hydronium ions to another compound — for example, hydrochloric acid gives H+ ions to compounds it reacts with. Brønsted-Lowry bases are compounds that can accept hydronium