A neutralization reaction is a chemical reaction between an acid and a base which produces a more neutral solution (closer to a pH of 7). The final pH depends on the strength of the acid and base in the reaction. At the end of a neutralization reaction in water, no excess hydrogen or hydroxide ions remain.
The classic example of a neutralization is the reaction between an acid and a base to yield a salt and water:
acid + base → salt + water
HCl + NaOH → NaCl + H2O
The right arrow indicates the reaction completes to form the product. While the classic example is valid, a more general expression based on Bronsted-Lowry acid-base theory is:
AH + B → A + BH
HSO4- + OH- → SO42- + H2O
is also an example of a neutralization reaction.
Strong vs Weak Acids and Bases
While strong acids and strong bases completely dissociate, weak acids and bases only partially dissociate to form an equilibrium mixture. The neutralization remains incomplete. Thus, the right arrow is replaced by arrows pointing both toward products and reactants. An example of a neutralization with a weak acid and base would be:
AH + B ⇌ A- + BH+
- Steven S. Zumdahl (2009). Chemical Principles (6th ed.). New York: Houghton Mifflin Company. pp. 319-324.