Warmup
• What type of
titration?
• What is the
pKa of the
acid being
titrated?
• Why is
equivalence
point at pH =
9?
Warmup
• Strong base
– weak acid
titration
• The pKa of
the acid is
4.5.
• The
conjugate
base of the
acid is also a
base.
Agenda
Strong vs. Weak Acid Warmup
Notes: Salt Hydrolysis Chapter 8
Short Kahoot: Acids Bases Buffers
Classwork:
• Testing Salts Activity
• Practice Problems - Worksheets
Quiz next week: Acids, Bases, Buffers
Salt Hydrolysis
How to determine if a salt is neutral, basic or
acidic?
• In the salt, identify the:
Cation
Anion
• Next, determine if either is:
Conjugate of a weak acid or base
Conjugate of a strong acid or base
Certain small metal cations
Salt Hydrolysis
How to determine if a salt is neutral, basic
or acidic?
Small cations that will be acidic:
Al3+
Cr3+
Al3+ + H2O ⇌ Al(OH)3 + H+
Fe3+
Bi3+
The small cation size allows it to
attract OH- ions leaving H+ ions to
Be2+
form an acidic solution.
Salt Hydrolysis
How to determine if a salt is neutral, basic or
acidic?
Conjugate bases of weak acids will be basic:
Ethanoic acid ⇌ Ethanoate
CH3COOAmmonia ⇌ Ammonium
NH4+
Hydrofluoric acid ⇌ Fluoride
FCarbonic Acid ⇌ Hydrogencarbonate HCO3CH3COO- + H2O ⇌ CH3COOH + OH-
The conjugate base will attract H+ creating a basic solution.
Salt Hydrolysis
How to determine if a salt is neutral, basic or
acidic?
Conjugate acids of weak bases will be acidic:
Ammonia ⇌ Ammonium
NH3 ⇌ NH4+
Diethylamine ⇌ Diethylammonium
NH4+ + H2O ⇌ NH3 + H3O+
The conjugate acid donates H+ creating an acidic solution.
Summary
• The equivalence point in a weak acid – strong
base is pH ____.
• The equivalence point in a strong acid – strong
base is pH ____.
• The equivalence point in a strong acid – weak
base is pH ____.
• The NH4+ ion is expected to be ___.
• The CO32- ion is expected to be ___.
• The Cl- ion is expected to be ___.
Summary
•
•
•
•
The NH4+ ion is expected to be acidic.
The CO32- ion is expected to be basic.
The Cl- ion is expected to be neutral.
The equivalence point in a weak acid – strong
base is pH > 7.
• The equivalence point in a strong acid – strong
base is pH = 7.
• The equivalence point in a strong acid – weak
base is pH < 7.
Agenda
Strong vs. Weak Acid Warmup
Notes: Salt Hydrolysis Chapter 8
Short Kahoot: Acids Bases Buffers
Classwork:
• Testing Salts Activity
• Practice Problems - Worksheets
Quiz next week: Acids, Bases, Buffers