© University of South Carolina Board of Trustees Calculate the pH in the titration of mL of M HCl with M NaOH after a) 0.00 mL strong acid problem pH = 0.7 b) mL strong acid problem pH = 1.1 c) mL water + spectators pH = 7.0 d) mL strong base problem pH =12.8 of base are added. Calculating a Titration Curve: Strong Acid + Strong Base

© University of South Carolina Board of Trustees Titration of a Strong Acid with Strong Base pH = 7.0 Spectator Ions

© University of South Carolina Board of Trustees Chapt. 16 More Acids and Bases Sec. 4-5 Titration: Weak Acid + Strong Base ( or weak base + strong acid)

© University of South Carolina Board of Trustees Titration of a Weak Acid with Strong Base pH > 7.0 Equivalence Point

© University of South Carolina Board of Trustees Calculate the pH in the titration of mL of M acetic acid ( K a = 1.8 x10 -5 ) with M NaOH after a) 0.00 mL weak acid problem pH = 2.72 a) 0.00 mL weak acid problem pH = 2.72 b) 5.00 mL c) mL d) mL of base are added. Calculating a Titration Curve: Weak Acid + Strong Base

© University of South Carolina Board of Trustees Calculate the pH in the titration of mL of M acetic acid ( K a = 1.8 x10 −5 ) with M NaOH after b) 5.00 mL a) 0.00 mL weak acid problem pH = 2.72 b) 5.00 mL c) mL d) mL of base are added. Calculating a Titration Curve: Weak Acid + Strong Base

© University of South Carolina Board of Trustees Calculate the pH in the titration of mL of M acetic acid ( K a = 1.8 x10 −5 ) with M NaOH after b) 5.00 mL buffer problem a) 0.00 mL weak acid problem pH = 2.72 b) 5.00 mL buffer problem c) mL d) mL of base are added. Calculating a Titration Curve: Weak Acid + Strong Base

© University of South Carolina Board of Trustees Calculate the pH in the titration of mL of M acetic acid ( K a = 1.8 x10 −5 ) with M NaOH after b) 5.00 mL buffer problem pH = 4.74 a) 0.00 mL weak acid problem pH = 2.72 b) 5.00 mL buffer problem pH = 4.74 c) mL d) mL of base are added. Calculating a Titration Curve: Weak Acid + Strong Base

© University of South Carolina Board of Trustees Weak Acid Titration Curve a b

© University of South Carolina Board of Trustees Calculate the pH in the titration of mL of M acetic acid ( K a = 1.8 x10 −5 ) with M NaOH after c) mL a) 0.00 mL weak acid problem pH = 2.72 b) 5.00 mL buffer problem pH = 4.74 c) mL d) mL of base are added. Calculating a Titration Curve: Weak Acid + Strong Base

© University of South Carolina Board of Trustees Calculate the pH in the titration of mL of M acetic acid ( K a = 1.8 x10 −5 ) with M NaOH after c) mL weak base problem a) 0.00 mL weak acid problem pH = 2.72 b) 5.00 mL buffer problem pH = 4.74 c) mL weak base problem d) mL of base are added. Calculating a Titration Curve: Weak Acid + Strong Base

© University of South Carolina Board of Trustees Calculate the pH in the titration of mL of M acetic acid ( K a = 1.8 x10 −5 ) with M NaOH after c) mL weak base problem pH = 8.95 a) 0.00 mL weak acid problem pH = 2.72 b) 5.00 mL buffer problem pH = 4.74 c) mL weak base problem pH = 8.95 d) mL of base are added. Calculating a Titration Curve: Weak Acid + Strong Base

© University of South Carolina Board of Trustees Weak Acid Titration Curve a b c pH = 8.95 Equivalence Point

© University of South Carolina Board of Trustees Calculate the pH in the titration of mL of M acetic acid ( K a = 1.8 x10 -5 ) with M NaOH after d) mL a) 0.00 mL weak acid problem pH = 2.72 b) 5.00 mL buffer problem pH = 4.74 c) mL weak base problem pH = 8.95 d) mL of base are added. Calculating a Titration Curve: Weak Acid + Strong Base

© University of South Carolina Board of Trustees Chapt. 15 Flashback Sec. 7 Mixtures of Acids (Bases)

© University of South Carolina Board of Trustees If an acid (base) is much weaker ( K a ~100 x smaller) than another acid (base) in the problem, ignore it. What is the pH of a solution that is M in HCl and M in HF? What is the pH of a solution that is M in HOCl and M in HF? Mixtures of Acids (Bases) strong acid weak acid K a = 3.0x10 −8 K a = 3.5x10 −4 pK a = 7.52 pK a = 3.46 (reverse)

© University of South Carolina Board of Trustees Calculate the pH in the titration of mL of M acetic acid ( K a = 1.8 x10 -5 ) with M NaOH after d) mL strong base problem a) 0.00 mL weak acid problem pH = 2.72 b) 5.00 mL buffer problem pH = 4.74 c) mL weak base problem pH = 8.95 d) mL strong base problem of base are added. Calculating a Titration Curve: Weak Acid + Strong Base

© University of South Carolina Board of Trustees Calculate the pH in the titration of mL of M acetic acid ( K a = 1.8 x10 -5 ) with M NaOH after d) mL strong base problem pH =12.8 a) 0.00 mL weak acid problem pH = 2.72 b) 5.00 mL buffer problem pH = 4.74 c) mL weak base problem pH = 8.95 d) mL strong base problem pH =12.8 of base are added. Calculating a Titration Curve: Weak Acid + Strong Base

© University of South Carolina Board of Trustees Titration of a Weak Acid With Strong Base a b c d

© University of South Carolina Board of Trustees Student Example Calculate the pH in the titration of mL of M HOCl ( K a = 3.0 x10 −8 ) with M NaOH after 4.00 mL of base have been added.

© University of South Carolina Board of Trustees Chapt. 16 Sec. 6 Indicators

© University of South Carolina Board of Trustees pH Indicators acid solution unknown concentration strong base solution known concentration indicator dye changes color record volume of base

© University of South Carolina Board of Trustees pH Indicators Weak acid/base conjugate pair Acid and base forms are different colors Small amount used. Little affect on pH.

© University of South Carolina Board of Trustees Color Changes Near pK In In − HIn + H 2 O  In − + H 3 O + In − Look at [In − ]/[HIn] when pH = p K a - 1 pH = p K a pH = p K a % colored 50% colored 90% colored

© University of South Carolina Board of Trustees Strong-Acid / Strong-Base Titration Equivalence Point: pH and color change suddenly color change KaKa

© University of South Carolina Board of Trustees Color Change with 1 Drop

© University of South Carolina Board of Trustees Want p K a Indicator ~ pH of Equiv. Point

© University of South Carolina Board of Trustees pH Indicators Weak acid/base conjugate pair Acid and base forms are different colors Small amount used. Little affect on pH.

© University of South Carolina Board of Trustees Titration - Indicator Detection Equivalence Point: pH and color change suddenly color change KaKa