1. Titration

2. strong acids ionize almost completely weak acids don’t ionize very much [H 3 O +1 ] not same as acid concentration[H 3 O +1 ] not same as acid concentration

3. [H 3 O +1 ] can’t be measured directly determined by comparison

4. Acid-Base Titration carefully controlled neutralization rxncarefully controlled neutralization rxn requires:requires: –standard solution –standard solution & –acid-base indicator standard solution is: acid/base of known known concentration

5. Titration standard solution slowly added to unknown solution as solutions mix: – neutralization reaction occurs eventually: equivalence point – enough standard solution is added to neutralize the unknown solution  equivalence point

6. Equivalence point total # moles H +1 ions donated by acid = total # moles H +1 accepted by base so: total moles H +1 = total moles OH -1

7. Titration end-pointend-point: point at which indicator changes color – if indicator chosen correctly: end-point very close to equivalence point

8. Titration: strong acid with strong base volume of 0.100 M NaOH added (ml) pH 0- 14- 7- equivalence pt phenolphthalein color change: 8.2 to 10  0 ml  40m l   20 ml

9. M H+1 V H+1 = M OH-1 V OH-1 M H+1 = molarity of H +1 M OH-1 = molarity of OH -1 V H+1 = volume of H +1 V OH-1 = volume of OH -1

10. M a V a = M b V b [true for: –monoprotic acids with monohydroxy bases –diprotic acids with dihydroxy bases –triprotic acids with trihydroxy bases]

11. IF: # H’s in acid (M a )(V a ) = (M b )(V b ) ≠ # OH’s in base need to modify equation: (#H’s)(#OH’s)

12. Titration Problem #1 40.0 mL 35.0mL0.100M NaOH In a titration of 40.0 mL of a nitric acid solution, the end point was reached when 35.0mL of 0.100M NaOH was added. calculate the concentration of the nitric acid solution

13. Neutralization Reaction HNO 3 + NaOH  H 2 O + NaNO 3 HNO 3 is a monoprotic acid NaOH is a monohydroxy base

14. Variables M a = ? V a = 40.0 mL M b = 0.100 M V b = 35.0 mL #H’s = #OH’s = 1

15. Plug and Chug (1)(x) (40.0 mL) = (0.100 M )(35.0mL)(1) X = 0.875 M HNO 3

16. Titration Problem #2 What is the concentration of a hydrochloric acid solution50.0 mL 0.250M KOH 20.0mL of an HCl solutionWhat is the concentration of a hydrochloric acid solution if 50.0 mL of a 0.250M KOH solution is needed to neutralize 20.0mL of an HCl solution of unknown concentration?

17. Neutralization Reaction KOH + HCl  H 2 O + KCl HNO 3 is a monoprotic acid KOH is a monohydroxy base

18. Variables M a = X V a = 20.0 mL M b = 0.250 M V b = 50.0 mL #H’s = #OH’s = 1

19. Plug and Chug (1)(X)(20.0 mL) = (0.250 M) (50.0 mL)(1) X = 0.625 M HCl

20. Titration Problem #3 What is the concentration of a sulfuric acid solution50.0mL of a 0.25 M KOH 20.0mL of the H 2 SO 4 solutionWhat is the concentration of a sulfuric acid solution if 50.0mL of a 0.25 M KOH solution is needed to neutralize 20.0mL of the H 2 SO 4 solution of unknown concentration?

21. Neutralization Reaction H 2 SO 4 + 2 KOH  2 H 2 O + K 2 SO 4 H 2 SO 4 is a diprotic acid KOH is a monohydroxy base

22. Variables M a = X V a = 20.0mL M b = 0.25M V b = 50.0mL #H’s = 2 #OH’s = 1

23. Plug and Chug (2)(X)(20.0ml) = (0.25M)(50.0ml)(1) X = 0.3125 M H 2 SO 4 (sulfuric acid)