1. Indicators Substances that change color to signal the end of a titration.

2. Indicators the end point ≠ the equivalence point.

3. Indicators Substances that change color to signal the end of a titration. the end point ≠ the equivalence point When chosen properly, the endpoint and equivalence point occur simultaneously (within experimental error).

4. Indicators are weak acids or weak bases. HIn (aq) ⇌ H + (aq) + In − (aq) color 1 color 2

5. Indicators are weak acids or weak bases. HIn (aq) ⇌ H + (aq) + In − (aq) color 1 color 2 Bromthymol blue HIn (acid) formIn − (base) form

6. The color observed for the indicator during an acid-base titration depends on the ratio

7. The indicator color change is visible over a pH range given approximately by indicator pK In ± 1. K In = 1.0 x 10 −7, pK In = 7 Useful pH range is 7 ± 1 Bromthymol blue

8. The indicator color change is visible over a pH range given approximately by indicator pK In ± 1. K In = 1.0 x 10 −7, pK In = 7 Useful pH range is 7 ± 1 At or below a pH of 6 the indicator is yellow. Bromthymol blue

9. The indicator color change is visible over a pH range given approximately by indicator pK In ± 1. K In = 1.0 x 10 −7, pK In = 7 Useful pH range is 7 ± 1 At or below a pH of 6 the indicator is yellow. At pH 7 it is pale green. Bromthymol blue

10. The indicator color change is visible over a pH range given approximately by indicator pK In ± 1. K In = 1.0 x 10 −7, pK In = 7 Useful pH range is 7 ± 1 At or below a pH of 6 the indicator is yellow. At pH 7 it is pale green. At pH 8 and above, the color is blue. Bromthymol blue

11. Always choose an indicator that changes color at or slightly after the equivalence point.

12. The titration of 0.100 M HCl with 0.100 M NaOH.

13. The titration of a weak base, NH 3, by a strong acid, HCl.

14. Titration of a polyprotic acid.