Calculate the [OH ‾ ], [H+], and the pH of 0.16 M solutions of each of the following amines.

Question

(a) triethylamine [(C2H5)3N, Kb = 4.0 10-4]
(b) hydroxylamine (HONH2, Kb = 1.1 10-8)

Answer 1

Let's represent (C2H5O3N as B3N.
.............B3N + HOH ==> B3NH^+ + OH^-
initial......0.16...........0........0
change.......-x.............x........x
equil......0.16-x...........x........x

Kb = (B3BH^+)(OH^-)/(B3N)
Substitute Kb and from the ICE chart and solve for x = (OH^-). From that you can convert to pOH and to pH.
The second one is done the same way.