Final answer:
A buffer is a chemical compound that helps control the pH of a solution by adding or removing hydrogen ions. It resists dramatic changes in pH by being composed of certain pairs of solutes, such as a weak acid plus a salt derived from that weak acid, or a weak base plus a salt of that weak base.
Step-by-step explanation:
A buffer is a chemical compound that helps control the pH of a solution by adding or removing hydrogen ions. It resists dramatic changes in pH by being composed of certain pairs of solutes, such as a weak acid plus a salt derived from that weak acid, or a weak base plus a salt of that weak base.
For example, a buffer solution can be composed of dissolved acetic acid (a weak acid) and sodium acetate (the salt derived from that weak acid). Another example is a solution containing ammonia (a weak base) and ammonium chloride (a salt derived from that weak base).
Buffers play an important role in maintaining stable pH conditions, particularly in biological systems.