Chemicals and Solutions:
0.1 M Acetic acid
Methyl orange indicator solution, dropper bottle
5 hydrometer cylinders
10 mL grad. cylinder
100 ml graduated cylinder
pH meter and digital display
buffer array of methyl orange indicator
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.
Add methyl orange indicator to each concentration of acetic acid and compare the color to the buffer array.
Use the pH meter-digital display to take the pH of each concentration.
*Note* 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.
0.1 M acetic acid = pH 2.87
0.01 M acetic acid = pH 3.37
0.001 M acetic acid = pH 3.8
0.0001 M acetic acid = pH 4.3
0.00001 M acetic acid = pH
Vinegar is ~5% acetic acid solution which is ~0.9 M which is ~pH 2.4