Acid and Base Reactions
Shireen Rudina
ingegneria biologica
Equipe de dibattito
Arrhenius Theory
• In water, acids
dissociate to form H+
and bases dissociate to
form OHHCl + H2O  H3O++ Cl-
Concept Q: Which of these options are
only acids?
1. HCl, NH3, HI
2. H2CO3, NaOH, HBr
3. H2CO3, NH4+, HCl
4. HI, KOH, HBr
Arrhenius Strong/Weak Acids
• Strong acid
– Dissociates completely
HCl
HNO3
H2SO4
HBr
HI
HClO4
• Weak acids- everything
else
CH3COOH (aceto)
NH4+
Arrhenius Strong/Weak Bases
• Strong bases:
LiOH
NaOH
KOH
RbOH
CsOH
Ba(OH)2
Ca(OH)2
Sr(OH)2
• Weak bases: everything
else
In teams: Calculate the pH of a 0.05 M
HBr solution
1. Is HBr a strong acid?
How much does it
dissociate?
2. What is [H+]?
In teams: A 0.128 M solution of uric
acid (HC5H3N4O3) has a pH of 2.39.
Calculate the Ka of uric acid.
1. What is the equation
for Ka?
2. What variables do we
have?
• http://www.youtube.com/watch?v=YqEK5ECc
sDo
• http://www.youtube.com/watch?v=vyOnGA0c
mp0
• http://www.elmhurst.edu/~chm/vchembook/
183neutral.html
In teams: You have an unknown acid.
When you put 1 M in water, you see a
pH that corresponds to a specific
dissociation percentage.
• Find the Ka for the acid that dissociates:
– Team 1: 1%
– Team 2: 2%
– Team 3: 0.1%
• What acid do you have?
Arrhenius Acid/Base Reaction
Acid + Base = Salt + Water
HBr + NaOH NaBr + H2O
Neutralization
A Neutralization Experiment
Phenolphthalein:
Purple if pH > 7
Colorless if pH<7
CO2 + H2O --> H2CO3
Ca(OH)2 + H2CO3 -->
CaCO3 + 2 HOH
What is the result of a neutralization
reaction: NaOH + H2CO3?
1. NaH2 + H2O
2. NaH2 + H2O + CO3
3. NaHCO3 + H2O
4. NaCO3 + H2O
Bronsted-Lowry Acid/Base
Reaction
Conjugate acids and bases