Neutralization Reactions Prentice Hall Chapter 19.4 Dr. Yager

Objectives Define the products of an acid-base reaction Explain how acid-base titration is used to calculate the concentration of an acid or a base Explain the concept of equivalence in a neutralization reaction Describe the relationship between equivalence point and end point of a titration

Reactions of Acids and Bases In general, the reaction of an acid with a base produces water and one of a class of compounds called salts. Reactions in which an acid and a base react in an aqueous solution to produce a salt and water are generally called neutralization reactions.

Titration The process of adding a known amount of solution of known concentration to determine the concentration of another solution is called titration.

Equivalence Point When an acid and base are mixed, the equivalence point is when the number of moles of hydrogen ions equals the number of moles of hydroxide ions.

H3PO4 +3KOH → K3PO4 +3H2O

Doing a Titration The solution of known concentration is called the standard solution. Indicators are often used to determine when enough of the standard solution has been added to neutralize the acid or base. The point at which the indicator changes color is the end point of the titration. For a titration using a strong acid and a strong base, the point of neutralization is the end point of the titration.

Doing a Titration Added base is measured with a buret. Color change shows neutralization. Acid solution with indicator

H3PO4 + 3NaOH → Na3PO4 + 3H2O

1. When a neutralization takes place, one of the products is always carbon dioxide. a salt. sodium chloride. a precipitate.

1. When a neutralization takes place, one of the products is always carbon dioxide. a salt. sodium chloride. a precipitate.

2. In a titration, 45. 0 mL of KOH is neutralized by 75. 0 mL of 0 2. In a titration, 45.0 mL of KOH is neutralized by 75.0 mL of 0.30M HBr. What is the concentration of the KOH solution? 0.18M 0.60M 0.25M 0.50M

2. In a titration, 45. 0 mL of KOH is neutralized by 75. 0 mL of 0 2. In a titration, 45.0 mL of KOH is neutralized by 75.0 mL of 0.30M HBr. What is the concentration of the KOH solution? 0.18M 0.60M 0.25M 0.50M

3. How many moles of HCl are required to neutralize an aqueous solution of 2.0 mol Ca(OH)2?

3. How many moles of HCl are required to neutralize an aqueous solution of 2.0 mol Ca(OH)2?

H2SO4(aq) + 2NaOH(aq)  Na2SO4(aq) + 2H2O(aq) 4. In which of the following neutralization titrations of 1-molar solutions of H2SO4 and NaOH will the equivalence point be reached at the very end of the additions? H2SO4(aq) + 2NaOH(aq)  Na2SO4(aq) + 2H2O(aq) 200 mL of H2SO4 is slowly added to 100 mL of NaOH 200 mL of H2SO4 is slowly added to 200 mL of NaOH 100 mL of H2SO4 is slowly added to 200 mL of NaOH 100 mL of H2SO4 is slowly added to 100 mL of NaOH

H2SO4(aq) + 2NaOH(aq)  Na2SO4(aq) + 2H2O(aq) 4. In which of the following neutralization titrations of 1-molar solutions of H2SO4 and NaOH will the equivalence point be reached at the very end of the additions? H2SO4(aq) + 2NaOH(aq)  Na2SO4(aq) + 2H2O(aq) 200 mL of H2SO4 is slowly added to 100 mL of NaOH 200 mL of H2SO4 is slowly added to 200 mL of NaOH 100 mL of H2SO4 is slowly added to 200 mL of NaOH 100 mL of H2SO4 is slowly added to 100 mL of NaOH