Question

Write the expectations for pH at Equivalence in Acid–Base Titrations.

1. Titrating a strong acid with a strong base (OR vice versa)

Titrating a strong acid with a strong base (OR vice versa) pH at equivalence point:

2. Titrating a weak monoprotic acid with a strong base pH at 1⁄2 equivalence point:

pH at equivalence point:

3. Titrating a weak diprotic acid with a strong base pH at 1st 1⁄2 equivalence point:
pH at 1st equivalence point:
pH at 2nd 1⁄2 equivalence point:

pH at 2nd equivalence point:

4. Titrating a weak base with a strong acid pH at 1⁄2 equivalence point:
pH at equivalence point:

Answer 1

1. A strong acid-strong base titration is performed using a phenolphthalein indicator, because it changes color in a pH range between 8.3 - 10. It will appear pink in basic solutions and clear in acidic solutions. At the equivalence point, equal amounts of H⁺ and OH^- ions will combine to form H₂O, resulting in a pH of 7.0 (neutral). The pH at the equivalence point for this titration will always be 7.0.

2. 1/2 equivalence point is between 3-5 and equivalance point in between 5-7

3.

1st 1⁄2 equivalence point: between 3-5
pH at 1st equivalence point: 8-10
pH at 2nd 1⁄2 equivalence point: 11-13

pH at 2nd equivalence point:15-18

4. 1⁄2 equivalence point:8-10
pH at equivalence point:4-6