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Weak Acids - Tritration of Acetic Acid

Chemicals and Solutions

  • 0.1 M Acetic acid
  • Methyl orange indicator solution, dropper bottle

Materials

  • 5 hydrometer cylinders
  • 10 mL grad. cylinder
  • 100 ml graduated cylinder
  • pH meter and digital display
  • buffer array of methyl orange indicator
  • stir rods

Procedure

  1. Mark both sets of cylinders as follows: 10-1M, 10-2M, 10-3 M, 10-4 M, 10-5 M. Be sure to mark both sets of cylinders in this manner.
  2. Add methyl orange indicator to each concentration of acetic acid and compare the color to the buffer array.
  3. Use the pH meter-digital display to take the pH of each concentration.

Hint: This demonstration can be used in conjunction with demonstration Strong Acids - pH of HCl.

Discussion

Acetic acid solutions with the following concentrations have the pH indicated:

Concentration in
M acetic acid
pH
0.1 2.87
0.01 3.37
0.001 3.8
0.0001 4.3
0.00001

Vinegar is ~5% acetic acid solution which is ~0.9 M which is ~pH 2.4.

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