Theory of ACIDS AND BASES
Acids and bases are both electrolytes (conduct electricity in solution) because they both ionize in
solution.
According to the Arrhenius definiton:
Acids are substances that dissociate in water to produce one or more hydrogen ions, H+:
HCl(aq)  H+(aq) + Cl-(aq)
Bases are substances that dissociate in water to produce one or more hydroxide ions, OH -:
NaOH(aq)  Na+(aq) + OH-(aq)
Acids and bases are common household products. Acids and bases can be distinguished based on the
following properties: taste, feel, conductivity and response to indicators.
PROPERTY
ACIDS
BASES
TASTE
CONDUCTIVITY IN SOLUTION
FEEL OF SOLUTION
REACTION WITH LITMUS PAPER
REACTION WITH CARBONATES
REACTION WITH ACTIVE
METALS
PHENOLPHTHALEIN
BROMOTHYMOL BLUE
According to the Bronsted-Lowry definition:
An acid is a substance from which a proton (H+ ion) can be removed, and a base is a substance that
can remove a proton (H+ ion) from an acid.
NH3(g) + H2O(l)  NH4+(aq) + OH-(aq)
In this case, a proton went from the water to the ammonia gas. Water is the proton donor (acid) and
ammonia is the proton acceptor (base).
Since the ammonium ion (NH4+) can now potentially donate a proton it is called the conjugate
acid of the base ammonia (NH3).
Since the hydroxide ion (OH-) can now potentially accept a proton it is called the conjugate
base of water.