Acid and Base
Ch 15 and 16
acids
• 1. tastes sour.
• 2. conducts an electric current.
• 3. Causes certain dyes ( indicators) to change
color.
• 4. Liberates hydrogen when it reacts with certain
metals.
• 5. neutralizes basic solutions to form salts.
Bases
• 1. tastes bitter.
• 2. conducts an electric current.
• 3. causes certain dyes ( indicators) to change
color.
• 4. feels slippery.
• 5. neutralizes acid solution to form salts.
Definition of Acids and Bases
• An acid is a source of hydrogen ions (H+)
or hydronium ions (H3O+ ) in solution.
HCl(aq) + H2O(l)
(aq)
H3O+ (aq) + Cl-
• A base is a source of hydroxide ions (OH-)
e.g. NaOH(s)
Na+ (aq) + OH- (aq)
e.g. NH3 (aq) +H2O(l)
NH4+ (aq) + OH-(aq)
Naming of acids
1. In a binary acid, the negative anion
ends in -ide. The name begins with
the prefix hydro- , stem and ends
with -ic acid.
stem
hydro______ ic acid stem
hydroflouric acid
HF
hydrochloric acid
HCl
HBr
Hydrobromic acid
2. In an oxy acid, the negative anion
ends in –ate, use the stem and the
name ends with -ic acid.
______ ic acid
HNO3
H2SO4
H3PO4
CH3COOH
nitric acid
sulfuric acid
phosphoric acid
acetic acid
3. In an oxy acid, if the negative anion
ends in –ite, use the stem and the
name ends with -ous acid.
_______ ous acid
HNO2
nitrous acid
H2SO3
sulfurous acid
H3PO3
phosphorous acid
Some Common Bases
NaOH
Sodium hydroxide
KOH
Potassium hydroxide
Ba(OH)2
Barium hydroxide
Mg(OH)2
Magnesium hydroxide
Al(OH)3
Aluminum hydroxide
Learning Check
Match the formulas with the names:
A. ___ HNO2
1) hydrochloric acid
B. ___ Ca(OH)2
2) sulfuric acid
C. ___ H2SO4
3) sodium hydroxide
D. ___ HCl
4) nitrous acid
E. ___
5) calcium hydroxide
NaOH
Solution AB4
Match the formulas with the names:
A. _4__ HNO2
1) hydrochloric acid
B. _5__ Ca(OH)2 2) sulfuric acid
C. _2__ H2SO4
3) sodium hydroxide
D. _1__ HCl
4) nitrous acid
E. _3__ NaOH
5) calcium hydroxide
Learning Check
Acid, Base
or Salt
Name
CaCl2
______
_________________
KOH
______
_________________
Ba(OH)2 ______
_________________
HBr
______
_________________
H2SO4
______
__________________
Solution AB5
Acid, Base
or Salt
Name
CaCl2
salt
calcium chloride
KOH
base
potassiuim hydroxide
Ba(OH)2 base
barium hydroxide
HBr
acid
hydrobromic acid
H2SO4
acid
sulfuric acid
B. Definitions
• Arrhenius - In aqueous solution…
– Acids form hydronium ions (H3O+)
+
H3O
HCl + H2O
H
H
Cl
acid
O
H
H
–
+
O
H
+
Cl
H
–
Cl
B. Definitions
• Arrhenius - In aqueous solution…
– Bases form hydroxide ions (OH-)
NH3 + H2O
+
NH4
H
H
H
N
H
base
O
H
H
–
+
O
N
H
+
OH
H
H
H
B. Definitions
• Brønsted-Lowry
– Acids are proton (H+) donors.
– Bases are proton (H+) acceptors.
HCl + H2O 
acid
+
H3O
+
Cl
base
conjugate
acid
conjugate
base
Conjugate acid base pairs
• conjugate base: the species that
remains after an acid has given up a
proton
• conjugate acid: the species that is
formed when a base gains a proton
base
acid
NH3 + H2O
+
NH4
conjugate
acid
+
OH
conjugate
base
• In the two examples water first acts as a
base, then as an acid.
• Any species which can both accept and
receive protons is called amphiprotic.
(also known as amphoteric)
• Give the conjugate acid for each of the following:
Br
–
HBr
HSO4-
H2SO4
CO32-
HCO3-
• List the conjugate acids for the following
Bronsted bases
• OH
H2O
-
• CO3
2-
HCO3-
• NO3-
HNO3
• HCO3-
HCO3
• CN
-
HCN
• Give the conjugate base for each of the following:
HF
F-
H3PO4
H2PO4-
H3O+
H 2O
• Polyprotic - an acid with more than one H+
• List the conjugate bases for the following
Bronsted acids
• H2SO4
HSO4-
• HPO42-
PO43-
• HCO3
-
CO32-
• H3O+
H2O
• H2PO4-
HPO42-
Review 2: Name the acid, base, conjugate acid and base for each reaction.
CH3NH2 + H2O
base
H3O +
HC2H3O2 + H2O
acid
CH3NH3+
acid
base
+
conjugate base
H2PO4 base
H2PO4 -
+
conjugate acid
base
OH -
+
conjugate acid
acid
H3PO4 + H2O
acid
CH3NH3+
H3O +
conjugate base
+
conjugate acid
H3PO4
conjugate acid
C2H3O2 conjugate base
+
CH3NH2
conjugate base
Review 2: Name the acid, base, conjugate acid and base for each reaction.
H2PO42- + OH-
acid
base
HCN + H2O
acid
NH3
+
base
NO3base
CNconjugate base
H2O
NH4 +
HCO3 acid
+
conjugate base
base
acid
+
HPO4-
conjugate acid
H3O +
+
conjugate acid
+
conjugate acid
CO32conjugate base
H2O
OH conjugate base
+
HNO2
conjugate acid