Acids and Bases
Chapter 9
Acids
Have a sour taste. Vinegar owes its taste to acetic acid. Citrus fruits contain citric acid. React with certain metals to produce hydrogen gas. React with carbonates and bicarbonates to produce carbon dioxide gas
Bases
Have a bitter taste. Feel slippery. Many soaps contain bases.
Arrhenius acid is a substance that produces H+ (H3O+) in water
Arrhenius base is a substance that produces OH- in water
A Brønsted acid is a proton donor A Brønsted base is a proton acceptor
base base
acid acid
acid conjugate acid
base conjugate base
Definition of An Acid
Arrhenius acid is a substance that produces H+ (H3O+) in water A Brønsted acid is a proton donor A Lewis acid is a substance that can accept a pair of electrons A Lewis base is a substance that can donate a pair of electrons •• + OH •• acid base H+ •• H H+ + acid •• N H •• H O H •• H
+ H N H H
H base
Lewis Acids and Bases
H + •• N H H N H H
F F B F acid
F F B F
H base
No protons donated or accepted!
Acid-Base Properties of Water
H2O (l) H+ (aq) + OH- (aq)
autoionization of water
H O H + H O H base H2O + H2O acid
[
+ + H H O H O
]
-
H conjugate acid H3O+ + OHconjugate base
The Ion Product of Water
H2O (l) H+ (aq) + OH- (aq) [H+][OH-] Kc = [H2O] [H2O] = constant
Kc[H2O] = Kw = [H+][OH-] The ion-product constant (Kw) is the product of the molar concentrations of H+ and OH- ions at a particular temperature. Solution Is neutral acidic basic
[H+] = [OH-] At 250C Kw = [H+][OH-] = 1.0 x 10-14 [H+] > [OH-] [H+] < [OH-]
What is the concentration of OH- ions in a HCl solution whose hydrogen ion concentration is 1.3 M? Kw = [H+][OH-] = 1.0 x 10-14 [H+] = 1.3 M
Kw 1 x 10-14 = = 7.7 x 10-15 M [OH-] = [H+] 1.3
pH – A Measure of Acidity
pH = -log [H+]
Solution Is neutral acidic basic
[H+] = [OH-] [H+] > [OH-] [H+] < [OH-]
At 250C [H+] = 1 x 10-7 [H+] > 1 x 10-7 [H+] < 1 x 10-7
pH = 7 pH...