1. Topic: Neutralization Reaction Do Now:

2. Neutralization Reactions AcidAcid HX(aq)MOH(aq) HX(aq) + MOH(aq) → MX(aq) +H 2 O(l) +Base → Salt + Water DR rxn

3. Acid-Base Titration A procedure used in order to determine the unknown molarity of an acid or baseA procedure used in order to determine the unknown molarity of an acid or base M A V A = M B V B (molarity of acid)(volume of acid) = (molarity of base)(volume of base) You will know 3 out of the 4 variable Standard solution slowly added to unknown solution As solutions mix: – neutralization reaction occurs Eventually: – enough standard solution is added to neutralize the unknown solution

4. pH changes during neutralization Start with an acid Add a base At neutralization Start with a base Add an acid At neutralization pH < 7 pH  pH = 7 pH > 7 pH  pH = 7 acid-base indicator needed acid-base indicator needed WHY? WHY? Usually use phenolphalein Usually use phenolphalein WHY? WHY? When pH = 7 called equivalence point [H + ] = [OH - ]

5. Titration End-pointEnd-point = point at which indicator changes color – if indicator chosen correctly: end-point very close to equivalence point

6. M H +1 V H +1 = M OH -1 V OH -1 If you titrate H 2 SO 4 and NaOH 2H + 1OH +-

7. Titration Problem #1 40.0 mL 35.0mL 0.100M NaOHIn a titration of 40.0 mL of a nitric acid solution, the end point is reached when 35.0mL of 0.100M NaOH is added Calculate the concentration of the nitric acid solution HNO 3 + NaOH  H 2 O + NaNO 3

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

9. (1)(X) (40.0 mL) = (0.100 M )(35.0mL)(1) X = 0.875 M HNO 3

10. Titration Problem #2 What is the concentration of a hydrochloric acid solution50.0 mL 0.250M KOH 20.0mL of the 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 the HCl solution of unknown concentration? KOH + HCl  H 2 O + KCl

11. (1)(X)(20.0 mL) = (0.250 M) (50.0 mL)(1) X = 0.625 M HCl

12. 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? H 2 SO 4 + 2 KOH  2 H 2 O + K 2 SO 4

13. (2)(X)(20.0ml) = (0.25M)(50.0ml)(1) X = 0.3125 M H 2 SO 4 (sulfuric acid)