2: Acids and bases

Terms in this set (18)

acid (Brønsted-Lowry)
A substance that donates a proton (H+)
base (Brønsted-Lowry)
A substance that accepts a proton (H+)
conjugate base
The product formed when an acid loses a proton
conjugate acid
The product formed when a base gains a proton
acidity constant (Ka)
pKa
strong acid
A substance with a low pKa
weak acid
A substance with a high pKa
cation
A positively charged species
anion
A negatively charged species
zwitterion
A species with separate positively and negatively charged groups
Lewis acid
An electron pair acceptor
Lewis base
An electron pair donor
HSAB theory (Pearson acid-base theory)
Hard and soft acids and bases
hard acid
Acids which tend to have:
• small radii
• high oxidation state
• low polarizability
• high energy LUMO
• affinity for ionic bonding
hard base
Bases which tend to have:
• small radii
• high oxidation state
• low polarizability
• low energy HOMO
• affinity for ionic bonding
soft acid
Acids which tend to have:
• large radii
• low or zero oxidation state
• high polarizability
• lower energy LUMO
• affinity for covalent bonding
soft base
Bases which tend to have:
• large radii
• low or zero oxidation state
• high polarizability
• higher energy HOMO
• affinity for covalent bonding
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