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You need to prepare an acetate buffer of pH 5.92 from a 0.819 M acetic acid solution and a 2.56 M KOH solution. If you have 775 mL of the acetic acid solution, how many milliliters of the KOH solution do you need to add to make a buffer of pH 5.92? The pKa of acetic acid is 4.76.

Respuesta :

Answer:

V KOH = 247.939 mL

Explanation:

at the point of equilibrium:

mol CH3COOH = mol KOH.......for weak acid system - strong bases...(1)

⇒ mol CH3COOH = 0.775L * 0.819 mol / L

⇒ mol CH3COOH = 0.634 mol CH3COOH.....(2)

replacing (2) in (1):

0.634 mol = V KOH * 2.56 mol / L

⇒ V KOH = 0.634 mol / (2.56 mol / L )

⇒ V KOH = 0.247939 L ( 247.939 mL )

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