Neutralization (chemistry)
In chemistry, neutralization is understood as the reaction of equal amounts of acids and bases .
The reactions usually take place in aqueous solutions. Strong acids form completely dissolved H 3 O + ions in water , strong bases form completely dissolved OH - ions. If such solutions are combined, oxonium ions and hydroxide ions react to form water.
- Acid + base reacts to form water
An acid and a base are completely neutralized when the neutral point , i.e. pH 7, is reached. The neutralization releases large amounts of energy, it is an exothermic reaction , thermal energy, the heat of neutralization , is released. The severity of the reaction increases with the concentration used: While there are hardly any visible effects in a reaction with concentrations of c = 1 mol / l , neutralizations with high concentrations of the reactants (e.g. with 98 percent sulfuric acid ) may be extremely effective violent and are accordingly dangerous.
- Sample reaction
- Hydrochloric acid + sodium hydroxide solution reacts to form sodium chloride dissolved in water and water [(aq) = hydrate shell ].
If a weak acid (low degree of dissociation ) is neutralized with a strong base (high degree of dissociation) or a weak base is neutralized with a strong acid, the pH value at which there is complete neutralization can be interpreted differently. The pH value 7 corresponds to the value of pure water and is called neutral. The components of the acids and bases are not present in the same amount at the neutral point. In chemistry, with complete neutralization, the pH value at the equivalence point is preferably referred to as neutral. Here, acids and bases are present in the same amount, but the pH value deviates from 7.
See also
Web links
- Five examples of neutralization reactions , Jens Liebenau, Scribd