List of Acids and Bases


ACIDS  Strongest to weakest


HClO4                          perchloric acid                         

HI                                hydroiodic acid

HBr                              hydrobromic acid

HCl                              hydrochloric acid

HNO3                          nitric acid

H2SO4                          sulfuric acid   (diprotic)

CH3COOH                  acetic acid

HCOOH                      formic acid

HF                               hydrofluoric acid

HCN                            hydrocyanic acid

HNO2                          nitrous acid

HSO4-                         hydrogen sulfate ion


BASES  Strongest to weakest


NaOH                          sodium hydroxide

KOH                           potassium hydroxide

Ba(OH)2                      barium hydroxide

NH3                             ammonia

CH3NH2                      methylamine

C5H5N                         pyridine


Remember that Arrhenius defines an acid as a H+ producer and a base as an OH- producer.  So find the ionizing H on each acid and the ionizing OH on each base in the list above.


The strength of the acid or base depends on how many H+ ions (acid) or OH- ions (base) completely ionize, caused by the dissociation of the acid or base when they dissolve in water.  Think of dissociation as the process in which the H dissolves in water to form H+ and the OH dissolves in water to form OH-


Strong acids, at equilibrium, completely dissociate in water, which is to say that 100% of the acid molecules dissolve, leaving their molecules separated into H+ and a (-) monatomic or polyatomic anion the hydrogen was attached with.  In weak acids only a small percentage of the acid molecules dissociate into H+ and the attached anion at equilibrium. 


Study the list of the common acids placed in order from strongest to weakest.


The concept of a strong base can be related with what you learned about strong acids, only this time when a strong base dissociates, it completely ionizes all (100%) of its OH- ions on the attached cation, at equilibrium.  Weak bases do not completely dissociate, at equilibrium, in water.


Study  the list of the common bases placed in order from strongest to weakest.  Notice not all bases have a OH- ion, 


You will learn 2 other definitions that describe acids and bases later this year.  Then you will learn why ammonia, which does not have an OH- can act like a base.


 In the mean time be familiar with this list and the order of strong acids and to weak acids and strong  bases to weak bases.