Skill 10.5 Analyzing the composition and function of buffer solutions

Skill 10.5 Analyzing the composition and function of buffer solutions 

A buffer solution is a solution that resists a change in pH after addition of small amounts of an acid or a base. Buffer solutions require the presence of an acid to neutralize an added base and also the presence of a base to neutralize an added acid. These two components present in the buffer also must not neutralize each other A conjugate acid-base pair is present in buffers to fulfill these requirements. Buffers are prepared by mixing together a weak acid or base and a salt of the acid or base that provides the conjugate. 

Consider the buffer solution prepared by mixing together acetic acid— 

HC2H3O2—and sodium acetate—C2H3O2 containing Na as a spectator ion. 

The equilibrium reaction for this acid/conjugate base pair is  

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