What color is phenolphthalein in
a basic solution?
A.) Blue
An aqueous solution of an ionic
compound turns red litmus blue,
conducts electricity, and reacts
with an acid to form a salt and
water. This compound could be
B.) Pink
A.) HCl
C.) Yellow
B.) NaI
D.) Colorless
C.) KNO3
D.) LiOH
Arrhenius Acids & Bases
•  Arrhenius Acid – a substance that
ionizes to form H+ ions in aqueous
solutions
HCl(aq) ! H+(aq)+ Cl-(aq)
•  Arrhenius Base – a substance that
ionizes to form OH- ions in aqueous
solutions
NaOH(aq) ! Na+(aq)+ OH-(aq)
Which substance can be
classified as an Arrhenius acid?
A.) HCl
B.) NaCl
C.) LiOH
D.) KOH
Starts with H
Which substance is classified as
an Arrhenius base?
A.) HCl
B.) NaOH
Ends in OH
C.) LiNO3
D.) KHCO3
Bronsted-Lowry Acids & Bases
•  Bronsted-Lowry Acid – proton (H+) donor
•  Bronsted-Lowry Base – proton (H+) acceptor
According to the BronstedLowry theory, H2O is considered
to be a base when it
Conjugate Acids-Base Pairs
D.) accepts a proton
•  Two substances that are related by the
loss or gain of a single hydrogen ion
•  Conjugate Acid – the particle formed
when a base gains a hydrogen ion
•  Conjugate Base – the particle that
remains when an acid has donated a
hydrogen ion
•  What is the conjugate base of HCl? Cl•  What is the conjugate acid of HSO4-? H2SO4
What is the conjugate base of
NH3?
The conjugate acid of the HSion is
A.) NH4+
A.) H+
B.) NH2-
B.) S-2
C.) NO3-
C.) H2O
D.) NH4
D.) H2S
A.) donates an electron
B.) accepts an electron
C.) donates a proton
Examples
•  NH3 + H2O 䊽 NH4+ + OH-
B
A
CA
CB
•  HCl + CO3-2 䊽 Cl- + HCO3-
A
B
CB
CA
•  H2O + HCN 䊽 H3O+ + CN-
B
A
CA
CB
A = Acid
B = Base
CA = Conj Acid
CB = Conj Base