1
Conjugate acids and
bases
Different definitions of
acids and bases
• Arrhenius definition
• acids generate H
3
O
+
in water
• bases generate OH
-
in water
• Brønsted Lowry definition
• Acids are proton donors
• Bases are proton acceptors
• which is an acid/base?
• HF + H
2
O H
3
O
+
+ F
-
• CH
3
NH
2
+ H
2
O CH
3
NH
3+
+ OH
-
• By Arrhenius, HF is an acid, is a CH
3
NH
2
base.
Follow the proton
• HF + H
2
O H
3
O
+
+ F
-
• CH
3
NH
2
+ H
2
O CH
3
NH
3 +
+OH
-
• What about the reverse reaction?
H
+
H
+
H
+
H
+
