An acid can be described as a substance that dissociates
___1___ one or more
hydrogen ions and one or more negative ions ( anions ).
Thus an acid can also be defined as a proton donor.
Acidic solutions contain more H+ than OH- and have a pH
lower than 7. Acids are found in many different
substances. Citrus fruit such as lemons and oranges
contain citric acid, sour milk contains lactic acid and
vinegar contains acetic acid. A base is a substance
that dissociates into one or more position ions (
cations ) plus one or more negatively charged hydroxide
ions that can accept, or ___2___
with protons. Thus, sodium hydroxide ( NaOH ) is a base
because it dissociates to release OH-, which has a
strong attraction for protons. Bases ___3___
bitter and feel slippery. Milk of magnesia, ammonia, and
soap are bitter tasting substances that contain bases.
Some acids and bases are dangerous, corrosive
compounds. Hydrochloric acid and sodium hydroxide can
each cause burns if they are spilled on the skin.
However, different compounds are formed when acids and
bases are mixed ___4___.
For example, when hydrochloric acid and sodium hydroxide
are mixed together, they form sodium chloride and water.
Sodium chloride is a harmless substance known as table
salt. The reaction between and acid and a base forms a
neutral substance known as a salt. Thus, a salt is a
substance that dissociates in water into cations and
anions, ___5___ of
which is H+ or OH-. |