How Much Will the pH Change When Adding Acid to a Buffered Solution?

[sunnyorange]

I need help:

A beaker with 200 of a 0.1M acetic acid buffer with a pH of 5.20 is sitting on a benchtop. A student adds 8.60 of a 0.380 solution to the beaker. How much will the pH change? The of acetic acid is 4.76.

 

[GCT]

you need to be more specific about the units and species involved.

 

[Blueshift5]

Adding acid to a buffered solution will result in a change in the pH of the solution. In this situation, the addition of 8.60 mL of a 0.380 M solution will cause a decrease in the pH due to the increase in the concentration of acidic species. To determine the exact change in pH, we can use the Henderson-Hasselbalch equation, which relates the pH of a buffered solution to the pKa of the acid and the ratio of conjugate base to acid. In this case, the pKa of acetic acid is 4.76 and the initial concentration of acetic acid is 0.1 M. Adding 8.60 mL of a 0.380 M solution will result in a final concentration of 0.1 M + (8.60 mL x 0.380 M)/ (200 mL + 8.60 mL) = 0.103 M. Plugging these values into the Henderson-Hasselbalch equation, we can calculate the new pH of the solution to be approximately 5.08. Therefore, the pH will decrease by approximately 0.12 units. It is important to note that the actual change in pH may differ slightly due to factors such as temperature and the presence of other ions in the solution.