Hydrolysis of Salts:
Hydrolysis reactions are general reactions in which the water
molecule takes part in the reaction as one of the reactants.
This reaction is observed in many reactions both in inorganic
and organic chemistry. The hydrolysis of salts is really the
reverse of the neutralization reaction.
Do you expect that salts are capable of changing the acids
or bases in water? On the basis of previously learned principles
you probably should say "NO". Salts have neither H+
or OH- ions in their formulas.
Other bases do not have hydroxide ions in the formula, but
readily react with water to produce hydroxide ions. These bases
include sodium carbonate and phosphate.
Note that the hydrolysis equation is a double replacement
Na2CO3 + 2 H20 ---> 2Na+
+ 2 OH- + H2CO3
Water is the Bronsted Acid and sodium carbonate is the Bronsted
Base. The results of the hydrolysis reaction are the formation
of a weak acid and a strongly ionized base. The strongly ionized
base gives the overall property of basic.
In the graphic on the left, the solution in the beaker is
a mixture of Arm and Hammer Sodium Carbonate detergent. The pink
hands are from the the indicator phenolphthalein which turns
pink in the presence of hydroxide ions or base. Most detergents
have the property of being basic which contributes to the cleaning