1. Unit 13 – Acid, Bases, & Salts
Section 3 - Titrations
Print 1, 3-5, 7-8

2. ACID + BASE  SALT + WATER
Neutralization Reactions (REVIEW)
Neutralization – chemical reaction between an acid and a base.
HCl + NaOH  NaCl + HOH
H2O =
ACID + BASE  SALT + WATER

3. Titration
Titration
Process used to determine the concentration of a solution by adding a known concentration (the standard) to a measured amount of the solution of unknown concentration

4. Titration
Equivalence Point
moles of H+ = moles of OH–

5. Titration
A steep rise in the pH of the acid solution indicates that all the H+ ions from the acid have been neutralized by the OH- ions of the base.

6. Titration
End Point
indicator permanently changes color

7. Titration
Phenolphthalein

8. Acid/Base Indicators

9. Example #1:
A 159 mL sample of KOH is titrated to equivalence with 100. mL of 1.50 M H2SO4 . Calculate the molarity of the of the KOH solution. H2SO4(aq) + 2 KOH(aq)  2 H2O(l) + K2SO4(aq)
V = L
V = L
M = 1.50 mol/L
M = ? mol/L
1.50
mol H2SO4 2
mol KOH
mol KOH x =
0.100 L H2SO4 x 1
L H2SO4 1
mol H2SO4
L of HA
molarity HA
molarity BOH
0.300 mol KOH
= _____ M KOH
1.89 M KOH
0.159 L KOH

10. Example #2: HBr(aq) + NaOH(aq)  H2O(l) + NaBr(aq)
Hydrobromic acid is titrated to equivalence with sodium hydroxide.
What volume of 1.50 M HBr is needed to react with 120. L of 1.25 M of NaOH ?
HBr(aq) NaOH(aq)  H2O(l) + NaBr(aq)
V = ? L
V = 120. L
M = 1.50 mol/L
M = 1.25 mol/L
molarity HA
1.25
mol NaOH 1
mol HBr 1
L HBr x x
120 L NaOH x 1
L NaOH 1
mol NaOH
1.50
mol HBr
L of BOH
molarity BOH
= ____L HBr
100 L HBr

11. Quick Quiz!
1) When the moles of acid equals the moles of base you have reached the…
A) titration point
B) end point
C) equivalence point
D) neutralization point 11

12. Quick Quiz.
2) If 20. mL of 0.50 M HCl is titrated to equivalence by 40. mL of NaOH, then the NaOH concentration must be ___.
A) 2.0 M
B) 1.0 M
C) 0.50 M
D) 0.25 M
moles of H+ = moles of OH–
0.020 L
0.50 M
0.040 L
??? M 12