1. Make up 50 ml solutions of 0.15 M KH2PO4 and 0.15 M K2HPO4.
Note: Dissolve the chemical thoroughly in a beaker with approximately 40
ml distilled water. Then transfer the solution to a measuring cylinder and
top up to 50ml.
2. Measure the pH of both solutions.
3. Make up a solution of 150 mM Pi buffer pH 6.5 by mixing the solutions of
KH2PO4 and K2HPO4. Record the volume of K2HPO4 solution used.
Note: This can be achieved by putting 50 ml of one solution (KH2PO4) in a
beaker with a magnetic bar. Stir at moderate speed on the stirrer while
measuring the pH. Add the other phosphate solution (K2HPO4) until the
pH of 6.5 is obtained.
4. Keep this buffer solution for Part C.