Question

A. Preparation of Acetic Acid-Acetate Buffer Solution An acetate buffer contains the acid-base pair, acetic acid and the acetate fon (typically added as sodium acetate). For acetic acid, pk, = -log (1.8 10 = 4.74. Consider the con ditions that will yield 100 ml of an acetate buffer solution with a pH < 4.74. Equation (7) indicates that if the log term is to be zero, the concentrations of the conjugate acid (acetic acid) and the conjugate base (acetate ion) must be equal. Because the conjugate base, sodium acetate, will be dissolved in the same volume that contains the 10 mmol of acetic acid, we must add 10 mmol of the sodium acetate to the acid. The resulting buffer volume may be slightly larger than the original 100 mL of acid because of the volume taken up by the sodium acetate in solution. Students should be aware that sodium acetate may be available as the "anhydrous" salt (CH.COONa) or as a hydrated salt (CH,COONa.nH2O). The 10 mmol mass of sodium acetate must be determined using the correct molecular weight. 1. Measure 100 ml of 0.10 M acetic acid in a graduated cylinder. 2. Transfer it to a 250-ml beaker and measure and record the pH. The sodium acetate will be added to this solution. Save it and do not contaminate it. 3. Calculate the quantity of sodium acetate needed to make the acetate buffer. Record your calculations in lab notebook. Make sure to obtain the correct information as to the sodium acetate from the label on the bottle. no 4. To 100 mL of 0.10 M acetic acid, add 10 mmol of sodium acetate and stir the mixture until all of the sodium acetate dissolves. 5. Measure and record the pH. If necessary, prior to making this measurement calibrate your pH meter according to directions provided by your TA.

With this information how would I calculate the pH of .01 M Ammonia solution and the pH of .01 M Ammonia buffer solution

I need Ph of acetic acid! sorry for the wrong wording!

Answer 1

To calculate the specific pH of a given buffer, you need to use the Henderson-Hasselbalch equation for acidic buffer pH = pKa + log10([A-]/[HA])," where Ka is the "dissociation constant" for the weak acid, [A-] is the concentration of conjugate base and [HA] is the concentration of the weak acid.