In: Chemistry
What is the pOH of 0.0042 M LiF?
Ka = 7.1 x 10-4
7.39 |
11.24 |
6.61 |
2.76 |
9.15 |
LiF -----------> F- + Li+
F- + H2O------------> HF + OH^-
I 0.0042 0 0
C -x +x +x
E 0.0042-x +x +x
Kb = Kw/Ka = 1*10^-14/7.1*10^-4 = 1.4*10^-11
Kb = [HF][OH-]/[F-]
1.4*10^-11 = x*x/0.0042-x
1.4*10^-11*(0.0042-x) = x^2
x = 2.42*10^-7
[OH-] = x = 2.42*10^-7M
POH = -log[OH-]
= -log2.42*10^-7 = 6.6161 >>>>>>answer