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) H3O+ (aq) + Cl- (aq)
• 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.
hydro______ ic acidHFHClHBr
hydroflouric acid
hydrochloric acid
Hydrobromic acid
stemstem
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
phosphoric acid
sulfuric 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
H2SO3
H3PO3
nitrous acid
sulfurous acid
phosphorous acid
Some Common Bases
NaOH
KOH
Ba(OH)2
Mg(OH)2
Al(OH)3
Sodium hydroxide
Potassium hydroxide
Barium hydroxide
Magnesium hydroxide
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. ___ NaOH 5) calcium hydroxide
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 Nameor Salt
CaCl2 ______ _________________
KOH ______ _________________
Ba(OH)2 ______ _________________
HBr ______ _________________
H2SO4 ______ __________________
Solution AB5
Acid, Base Nameor Salt
CaCl2 salt calcium chloride
KOH base potassiuim hydroxide
Ba(OH)2 base barium hydroxide
HBr acid hydrobromic acid
H2SO4 acid sulfuric acid
B. DefinitionsB. Definitions• ArrheniusArrhenius - In aqueous solution… - In aqueous solution…
HCl + H2O H3O+ + Cl–
– AcidsAcids form hydronium ions (H3O+)
H
HH H H
H
ClClO O
–+
acid
B. DefinitionsB. Definitions• ArrheniusArrhenius - In aqueous solution… - In aqueous solution…
– BasesBases form hydroxide ions (OH-)
NH3 + H2O NH4+ + OH-
H
H
HH H
H
N NO O–+
H
H
H H
base
B. DefinitionsB. Definitions• Brønsted-LowryBrønsted-Lowry
HCl + H2O H3O+ + Cl-
– AcidsAcids are proton (H+) donors. – BasesBases are proton (H+) acceptors.
conjugate base
conjugate acid
baseacid
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
NH3 + H2O NH4+ + OH-
conjugate base
conjugate acid
acidbase
• 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)
Br –
HSO4-
CO32-
HBr
H2SO4
HCO3-
• Give the conjugate acid for each of the following:
• List the conjugate acids for the following Bronsted bases
• OH -
• CO3 2-
• NO3-
• HCO3-
• CN -
H2O
HCO3-
HNO3
HCO3
HCN
F -
H2PO4-
H2O
HF
H3PO4
H3O+
• Give the conjugate base for each of the following:
• Polyprotic - an acid with more than one H - an acid with more than one H++
• List the conjugate bases for the following Bronsted acids
• H2SO4
• HPO42-
• HCO3-
• H3O+
• H2PO4-
HSO4-
PO43-
CO32-
H2O
HPO42-
Review 2: Name the acid, base, conjugate acid and base for each reaction.
CH3NH2 + H2O CH3NH3+ + OH -
H3PO4 + H2O H3O + + H2PO4 -
HC2H3O2 + H2O H3O + + C2H3O2 -
CH3NH3+ + H2PO4 - H3PO4 + CH3NH2
base
base
base
base
acid
acid
acid
acid
conjugate acid
conjugate acid
conjugate acid
conjugate acid
conjugate base
conjugate base
conjugate base
conjugate base
Review 2: Name the acid, base, conjugate acid and base for each reaction.
H2PO42- + OH- HPO4
- + H2O
HCN + H2O CN- + H3O +
NH3 + H2O NH4 + + OH -
NO3- + HCO3 - CO3
2- + HNO2
acid
base
acid
acid
base
acid
base
base
conjugate base
conjugate base
conjugate acid
conjugate base
conjugate acid
conjugate acid
conjugate base
conjugate acid