A weak acid with an initial pH of 3.2 was titrated with a strong base. 15 mL of 0.1 M NaOH was added to the acid to reach the equivalence point at a pH of 8.6. What would you expect the approximate pH of the analyte to be after the first 5 mL of 0.1 M NaOH was added?
7.2
3.4*
8.6
I think it's 3.4 because the solution would remain acidic, and then become basic quickly as it reaches the equivalence point on a titration graph- I am not 100% sure though. Please help!
I agree
To determine the approximate pH of the analyte after the first 5 mL of 0.1 M NaOH was added, we need to consider the concept of acid-base titration and the reaction that occurs during the titration.
During a titration, a solution containing the analyte (in this case, a weak acid) is gradually neutralized by adding a strong base (in this case, NaOH) until the equivalence point is reached. At the equivalence point, the moles of acid are exactly equal to the moles of base added. In this scenario, the equivalence point is reached when 15 mL of 0.1 M NaOH is added to the weak acid.
Now, let's analyze the situation. We start with a weak acid with an initial pH of 3.2, which means it is acidic. As the strong base is added, it reacts with the weak acid in a neutralization reaction. This reaction will cause the pH to increase.
The pH at the equivalence point is given as 8.6, indicating that the solution becomes basic. So, when 15 mL of NaOH is added, the pH rises from 3.2 (acidic) to 8.6 (basic).
Since we are asked to determine the approximate pH after the first 5 mL of NaOH was added, we can assume that we are still in the acidic range. The pH would have increased, but not yet reached the equivalence point of 8.6.
Considering the gradual nature of the titration, it is reasonable to expect that the pH after adding the first 5 mL of NaOH would be somewhere between the initial pH of 3.2 and the final pH of 8.6.
Based on the available answer choices, the most appropriate option is 3.4, as it is the closest pH value to the starting pH of 3.2. Remember that this is an estimation, and the exact pH value cannot be determined without further calculations or experimental data.
Overall, by understanding the concept of acid-base titration and the changes in pH during the process, we can make an informed prediction about the approximate pH after the first 5 mL of NaOH is added.