Acid-Base Titrations

1
Acid-Base Titrations

• Neutralization Reactions

2
Acid-Base Titrations

• Titrations are used to determine the
  concentration (molarity) of a base or acid with a
  known concentration of base or acid.
• The purpose of a titration is to determine the
  end point or equivalence point.
• The end point is where the number of moles of
  acid are equal to the number of moles of base
• H OH-
• When mixing a strong acid and a strong base the
  pH should equal 7 (neutralization)

3
Acid-Base Titrations
4
Acid-Base Titrations

• Here is what you need to determine the
  concentration of an acid
• The concentration of the base
• The amount of base used to neutralize the acid
  (This would be the end point)
• An indicator
• The amount of acid started with for the titration

5
Acid-Base Titrations

• The easy way to solve acid-base titrations
• nHCaVa nOHCbVb
• nH number of hydrogen ions for the acid
• Ca Concentration of Acid (Molarity)
• Va Volume of Acid
• nOH number of hydroxide ions for the base
• Cb Concentration of Base (Molarity)
• Vb Volume of Base

6
Acid-Base Titrations

• Lets try a problem
• What volume of 0.10 M NaOH is needed to
  neutralize 20.0 mL of 0.20 M HCl?
• nHCaVa nOHCbVb
• Givens
• Cb0.10 M NaOH
• Va 20.0 mL
• Ca 0.20 M HCl
• nOH NaOH ? 1 OH-
• nH HCl ? 1 H
• Vb ? mL

7
Acid-Base Titrations

• How to solve
• nHCaVa nOHCbVb

8
Acid-Base Titrations

• Lets try another problem
• 25.0 mL of HCl(aq) was neutralized by 50.0 mL of
  0.10 mol/L Ca(OH)2 solution. What was the
  concentration of HCl?
• nHCaVa nOHCbVb
• Givens
• Va 25.0 mL
• Cb0.10 M Ca(OH)2
• nOH Ca(OH)2 ? 2 OH-
• nH HCl ? 1 H
• Vb 50.0 mL
• Ca ? M HCl

9
Acid-Base Titrations

• How to solve
• nHCaVa nOHCbVb