3. What is the pH of a solution of 0.200 M
H
3
C
6
H
5
O
7
(citric acid)?
K
a
=
3.5 x 10
-4
We must always start with a balanced equation, so what is the ionization equilibrium for citric acid?
a)
H
3
C
6
H
5
O
7
(aq) + H
2
O (l)
H
+
(aq) + H
5
C
6
H
5
O
8
-
(aq)
b)
H
3
C
6
H
5
O
7
(aq) + H
2
O (l)
H
4
C
6
H
5
O
7
+
(aq) + OH
-
(aq)
c)
H
3
C
6
H
5
O
7
(aq)
H
+
(aq) + H
3
C
6
H
4
O
7
-
(aq)
d)
H
3
C
6
H
5
O
7
(aq)
H
+
(aq) + H
2
C
6
H
5
O
7
-
(aq)