Answer: The best choice for the titration would be Phenol red with a pH range of 6.8-8.2, as it closely matches the pH range of the color change during the titration process.
Explanation: Okay, let's go through the explanation step-by-step:
1. The graph shows the pH of the solution during the titration of an acid with 0.10 M NaOH. The pH starts around 2-3 and increases as more NaOH is added, eventually reaching a pH around 12-13.
2. The question asks which indicator would be the best choice for this titration, based on the pH range of the color change for each indicator.
3. Thymol blue has a pH range of 1.2-2.8, which is too low for this titration. The pH never drops below 2 in the given data.
4. Congo red has a pH range of 3.0-5.0, which is also too low for this titration.
5. Phenol red has a pH range of 6.8-8.2, which closely matches the pH range observed in the titration curve, specifically around the equivalence point where the pH changes rapidly.
6. Indigo carmine has a pH range of 11.6-14.0, which is too high for this titration. The pH never reaches that high.
Therefore, Phenol red would be the best choice of indicator for this titration, as its color change pH range aligns well with the observed pH changes during the titration process.
