Conjugate Acids and Bases
HC
2
H
3
O
2
is an acid.
NaC
2
H
3
O
2
is a base.
Because they differ by only one proton, they form a
conjugate acid-base pair
.
HC
2
H
3
O
2
<--> H
+
+ C
2
H
3
O
2
-
NH
4
+
<--> H
+
+ NH
3
H
2
CO
3
<--> H
+
+ HCO
3
-
HCO
3
-
<--> H
+
+ CO
3
2-
This concept is very important when describing
buffers
, where a mixture of an acid and its conjugate base is used to control the
pH
of a solution.