Question

You are given 1 liter of each of the following solutions: 1M HCl, 1M NaOH, 1M NH₃ , 1M HC₂H₃O₂ , 1MNH₄Cl, 1MNaC₂H₃O₂

a) Describe 4 different methods for preparing a buffer solution

b) Describe how you would prepare 400 ml a buffer with a pH= 4.74 and a buffer with pH= 9.25

c) Draw titration curves for : strong acid-strong base, strong acid-weak base, strong base-weak acid. Label the graph axes, indicate initial pH and pH at equivalence.   

Answer 1

a) The buffer solution consists of a 1) weak acid and its salt with strong base

                                                      2) weak base and its salt with a strong acid.

     1) Mixing 1MNH₄Cl & 1M NH₃    The volumes used should be different

      2) mixing 1M HC₂H₃O₂ , & 1MNaC₂H₃O₂     The volumes used should be different

      3) Mixing   1M HCl, & 1M NH₃   The volumes used should be different

       4) Mixing   1M NaOH & 1MNH₄Cl The volumes used should be different

B)   The Ka and Kb values are not given......we need that