8. Calculate the pH of a 0.050M solution of the weak base pyridine ( C5H5N ) if it has Kb = 1.7 x 10-4.

Balanced equation: C5H5N (aq) + H2O (l) HC5H5N+ (aq) + OH- (aq)

I.C.E. table:

C5H5N (aq) HC5H5N+ (aq) OH- (aq)
INITIAL
0.050M
0M
0M
CHANGE
-xM
+xM
+xM
EQUILIBRIUM
(0.050-x)M
xM
xM
Which of the following represents the Kb expression after substitution?
a) 1.7 x 10-4 = {(0.050-x)x} / {x}
b) 1.7 x 10-4 = {x2} / {0.050}
c) 1.7 x 10-4 = {(0.050-x)} / {x2}
d) 1.7 x 10-4 = {x2} / {(0.050-x)}