Buffers

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Buffers
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Buffers

• Resist changes in pH when a moderate amount of
  acid or base is added
• Must contain enough acid to react with any base
  that is added, and enough base to react with any
  acid that is added
• The acid and base components must not react in a
  neutralization reaction
• Solutions of a weak acid and the salt of its
  conjugate base OR a weak base and the salt of its
  conjugate acid

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Acetic Acid/Sodium Acetate Buffer

• Consider a buffered solution made by adding
  similar molar concentrations of acetic acid
  (CH3COOH) and its salt, sodium acetate (CH3COONa)
• Sodium acetate ionizes completely in water
• When an acid is added to the buffer, the acetate
  ion reacts with the hydronium ion to neutralize
  the solution
• When a base is added to the buffer, the acetic
  acid reacts with the hydroxide ions to neutralize
  the solution