H of a Buffer

Similarly, if a small amount of a base is added, it is consumed completely by the acetic 

To illustrate the function of a buffer, suppose that we have 1 L of the acetic acid-sodium acetate solution described previously. We can calculate the pH of the buffer using the procedure in Section 17.1  

The forward reaction is suppressed by the presence of the common ion, CHbCOO, and the reverse process is suppressed by the presence of CHsCOOH. 

As long as the amount cf strong acid added to the buffer does not exceed the amount of conjugate base originally present, all the added acid will be consumed and converted to weak acid. 

Because it is reasonable to as.sume that x will be very small, 

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The pH and [H+] of a buffer solution may be estimated using the Henderson-Hasselbalch equation ... 

Calculate the H of a buffer made with analytical concentrations 0.200 M lactic acid and 0.100 M sodium lactate. Repeat after a 100-fold dilution of the solution and compare the need for the full equation (3-2) in each case. Take a constant ionic strength of 0.10 M in both cases and use / values from the Kielland table in Appendix A-1, assuming lactate ion is about the same size as acetate. The reported pX° for lactic acid is 3.858. It is CH3CH(OH)COOH. 

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