1. ACIDS & BASES
 DEFINITIONS
1. Operational
2. Conceptual
a. Arrhenius
b. Bronsted-Lowry
c. Lewis
 AMPHOTERISM
1. water and ammonia
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2. polyprotic acids
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2. OPERATIONAL
DEFINITION based on experimental data
- These are definitions
using our senses with the help of colorimetric
instruments such as indicators (litmus,
phenolphthalein, methyl orange, etc.).
ACIDS BASES
• Electrolytes* • Electrolytes*
• Taste sour • With bitter taste
• Turn blue litmus • Feel slippery
red • Turn red litmus blue
• React with metal to • Pink  violet with
form H2 gas phph
• Colorless with phph • Yellow with methyl
ectrolytes can bemethyl
• Red with classified as weak or strong depending 2on it
orange
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6. CONCEPTUAL DEFINITION
- These are definitions of acids and bases based on
theories proposed by different scientists namely:
Acid Base
- yields - yields
Arrhenius hydrogen ion (H+) hydroxide ion
in aq’s solution (OH-) in aq’s
solution
- proton
Bronsted & Lowry
- proton donor
acceptor
Lewis - e- pair
acceptor
- e- pair donor
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7. Limitations of each definition:
• H+ vs. H3O+
• inability of compounds without OH_ to be a base
• hydrogen containing compounds that cannot donate
H+
• inability of compounds without H+ to be an acid
Example
s:
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8. Examples of Arrhenius acids &
bases
1) HCl → H+(aq) + Cl-(aq)
2) NaOH → Na+(aq) + OH-(aq)
3) CH3COOH → CH3COO-(aq) + H+(aq)
4) H2SO4 → H+(aq) + HSO4-(aq)
5) Ba(OH)2 → Ba2+(aq) + 2 OH-(aq)
6) KOH → K+(aq) + OH-(aq)
7) NaCl → Na+(aq) + Cl-(aq)
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9. Conjugate Acids & Bases
 A conjugate pair is composed of one
acid and one base.
1 2
1 2
Examples of Bronsted-Lowry acids &
bases
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11. Relative Strengths of Bronsted-Lowry
Acids & Bases
According to this theory, the strength of an
acid is measured by its tendency to donate a
proton, while that of a base is measured by
its tendency to accept a proton.
RULE 1: The stronger an acid is, the weaker its
conjugate base. The stronger the base is, the
weaker its conjugate acid.
RULE 2: Proton transfer reactions tend to favor
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12. A. Complete and identify the
conjugate acid-base pairs in the
following reactions:
1. NH3 + HF ⇔
 CN- + H2O ⇔
B. Complete the following acid-base
reactions & predict the direction of
the predominant proton transfer
reaction and show it by the lengths of
the arrows.:
 HCl + H2O →
 CH3COOH + H2O →
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13. Examples of Lewis acids & bases
1.Electron-deficient
molecules
2.Cations
3.Super-octet molecules
4.Molecules with multiple
bonds
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