Drop the Base Anger is an acid that can do more harm to the vessel in which it is stored than to anything on which it is poured. - Mark Twain

What we already know… Acids are solutions with hydronium ions in solution. Bases are solutions with hydroxide ions in solution. Acids and Bases can be classified as Strong if they ionize completely Acids and Bases can be classified as Weak if they do NOT ionize completely

What’s an Acid? Arrhenius – a substance that increase the number of [H+] ions when mixed with water Brǿwnsted-Lowry – substances that donate protons (H+) Lewis – a substance that can accept electrons Simplify Science Select LLC 2013©

Common Acids Acetic Acid Carbonic Acid Citric Acid Hydrochloric Acid Phosphoric Acid Sulfuric Acid Simplify Science Select LLC 2013©

What’s a Base? Arrhenius Base – a substance that increase the number of [OH] ions when mixed with water Brǿwnsted-Lowry Base – substances that accepts protons Lewis Base – a substance that can donates electrons Simplify Science Select LLC 2013©

Common Bases Acetone Ammonia Calcium hydroxide Lithium hydroxide Pyridine Sodium hydroxide Simplify Science Select LLC 2013©

All thumbs are fingers but not all fingers are thumbs… All Arrhenius acids are Brǿwnsted-Lowry acids, and all BL acids are Lewis acids Not all Lewis acids are Brǿwnsted-Lowry or Arrhenius acids Simplify Science Select LLC 2013©

Example Draw a mechanism showing how HCl acid meets the definition for each type of acid. Simplify Science Select LLC 2013©

Strong Acids & Strong Bases (MEMORIZE!) Strong Acids and Bases completely disassociate in water (Arrhenius). Simplify Science Select LLC 2013© NameChemical Formula Hydroiodic acid HI Hydrobromic acid HBr Perchloric acidHClO 4 Hydrochloric acid HCl Sulfuric acidH 2 SO 4 Nitric acidHNO 3 NameChemical Formula Sodium hydroxideNaOH Potassium hydroxideKOH lithium hydroxideLiOH Rubidium hydroxideRbOH Cessium hydroxideCsOH Calcium hydroxideCa(OH) 2 barium hydroxideBa(OH) 2 strontium hydroxideSr(OH) 2

Naming Acids Similar to polyatomic ions but one BIG change Anions Name Change -ate-ic -ous-ite -idehyrdo-____-ic

Naming Bases Bases follow the same rules as polyatomic ions. Name the cation followed by the anion (hydroxide) If the cation is a transition metal indicate the oxidation number

Conjugate Acids and Bases What about water?

Measuring Acid Strength pH = -log [H+] NameVariableDefinitionUnitsMeasured by Acid Strength pHLogarithmic measurement of the ability of a substance to form hydronium ions in solution NONEpH probe, litmus paper Hydrogen Ion Concentrati on [H + ]The concentration of hydronium ions present in solution MCalculated or Counted (not feasible)

Measuring Base Strength pOH = -log [OH - ] NameVariableDefinitionUnitsMeasured by Base Strength pOHLogarithmic measurement of the ability of a substance to form hydroxide ions in solution NONEpH probe, litmus paper Hydroxide Concentrati on [OH - ]The concentration of hydroxide ions present in solution MCalculated or Counted (not feasible)

pH Scale

Measuring Acid Strength pH probes Litmus Paper

Water Disassociation Water will disassociate by itself in a very small amount H 2 O  [H + ][OH - ] Kw = [H + ][OH - ] = 1.0 X [H 2 O]

Relating pH to pOH pH + pOH = 14 NameVariableDefinitionUnitsMeasured by Base Strength pOHLogarithmic measurement of the ability of a substance to form hydroxide ions in solution NONEpH probe, litmus paper Acid Strength pHLogarithmic measurement of the ability of a substance to form hydronium ions in solution NONEpH probe, litmus paper

Example B-1 H 2 SO 4 is a strong acid. What is the name, pH and pOH of a solution of a 15.8 M solution?

Example B-2 Write an equation for the ionization of water. What is the pH and pOH of water?

Example B-3 A has a pH of 3.6. How many hydronium ions are present in a 25 mL sample of solution?

Example B-4 What is the pH of a solution containing 1.4 X M [H+]? Classify the substance as an acid, neutral or base.

Acid Disassociation Acids and Bases disassociate very similar to ions HA  [H + ][A - ] We can write a disassociation expression as:

Strong Acids Strong Acids disassociate COMPLETELY (or close to it) The expression is meaningless/infinity And this simplifies to Initial Concentration of S.A. = Final Concentration of [H + ]

Weak Acids Weak Acids partially disassociate The expression is crucial to determining [H+] Concentration Initial Concentration of S.A. = Final Concentration of [H + ]

Example D-1 The acid disassociation constant for acetic acid is 1.58 X What is the pH of a solution of 0.15 M acetic acid? How does this compare to the pH of 0.15 M hydrochloric acid?

Base Disassociation Bases disassociate very similar to ions BOH  [B + ][OH - ] We can write a disassociation expression as:

Strong Bases Strong bases disassociate COMPLETELY (or close to it) The expression is meaningless/infinity And this simplifies to Initial Concentration of S.B. = Final Concentration of [OH - ]

Weak Bases Weak Bases partially disassociate The expression is crucial to determining [OH - ] Concentration Initial Concentration of S.B. = Final Concentration of [OH - ]

Example E-1 The disassociation constant for pyridine is 1.8 X What is the pH of a solution of 0.15 M pyridine?

Percent Ionization Percent Ionization = Concentration Ionized X 100 Original Concentration

Example D-1 Calculate the percent ionization for a solution of 0.01 M benzoic acid where Ka = 6.31 X