Chemistry: Acids and Bases
An acid is a solution that has an excess of hydrogen(H+) ions. A base is a solution that has an excess of hydroxide(OH-) ions. Another word for base is alkali. The strength of an acid or base can be either strong or weak.

* An acid that has a very low pH (0-4) are known as Strong acids.
* A base that has a very high pH (10-14) are known as Strong bases.
* An acid that only partially ionizes in an aqueous solution are known as Weak acids.
* A base that only partially ionizes in an aqueous solution are known as Weak bases.
strength of Acids and Bases and their formula.
Acid/base Type Formula
Acetic acid Weak acid CH3COOH
Formic acid Weak acid HCOOH
Hydrofluoric acid Weak acid HF
Hydrogen sulfide Weak acid H2S
Nitric acid Strong acid HNO3
Hydrochloric acid Strong acid HCl
Hydroiodic acid Strong acid Hl
Perchloric acid Strong acid HClO4
Ammonia Weak base NH3
pyridine Weak base C5H5N
Ammonium hydroxide Weak base NH4OH
Lithium hydroxide Strong Base LiOH
Potassium hydroxide Strong base KOH
Calcium hydroxide Strong Base Ca(OH)2
Barium hydroxide Strong Base Ba(OH)2