Question

Each group of students should prepare 100 mL of ONE of the following PAIRS of buffers

2. Phosphate buffer

a. 100 mM potassium-phosphate, pH 5.0

b. 100 mM potassium-phosphate, pH 7.0

To prepare 100 mL of 100 mM phosphate buffers by titrating the monobasic form with base, first calculate how much KH2PO4 you need. Dissolve this amount in 50 mL of water. Using the Henderson-Hasselbalch equation, calculate how much 1 M NaOH should be required to achieve the desired pH

3. Acetate buffer

a. 100 mM acetate buffer, pH 6.5

b. 100 mM acetate buffer, pH 4.5

We will mix appropriate amounts of 1 M acetic acid, solid sodium acetate and water. Using the Henderson-Hasselbalch equation, calculate how much acetic acid (1M) and sodium acetate should be required, and prepare the buffers accordingly.(pKa for acetic acid = 4.74)

Answer 1