Titration

What is It? Acid and base combined together Graph of pH as a function of volume of titrant is called a titration curve

Titration Curve for Strong Acid/Strong Base

Equivalence Point At equivalence point there is the same moles of acid and base No buffering occurs in strong acid and base titration What would curve for a strong base titrated by a strong acid look like?

Example How many ml of.50 M NaOH are required to reach the equivalence point by titrating 50.0 ml of.40M HBr?

Example: Strong Acid/Base 50.0 mL of 0.200M HNO 3 solution is titrated with 0.100M NaOH. What is the pH after the following amounts of base are added? a) 50.0 mL b) mL c) mL

Weak Acid/Strong Base Titration Curve pH starts higher Rapid rise and then levels into a zone where pH doesn’t change much (buffering zone) When enough base added to neutralize ½ acid – called half equivalence pt. (middle of buffer zone and pH = pK a ) pH at equivalence pt is greater than 7

What is the value for the K a of the weak acid titrated as shown?

Example Draw a titration curve for a weak base (pH = 11.5 and K b = 1.8 x ) titrated with a strong acid (pH = 1). On the curve indicate: a) Equivalence point b) Buffering zone c) Where pH = pK b d) Where pH depends only on base e) Where pH depends only on acid

Polyprotic Acid Curves