Calculate [ OH - ] of a 0.200 M solution of Pyridine C5H5N Kb = 1.70e-9
2007-03-11 11:15:50 · 3 answers · asked by tiggerx313 1 in Science & Mathematics ➔ Chemistry
kb= - log[h+] and h+ plus 0h- = 14
2007-03-11 11:20:56 · answer #1 · answered by fionnghaile 1 · 0⤊ 2⤋
Pyr+ H2O <--> PyrH+ + OH-
The equation for Kb will be:
Kb = [PyrH+][OH-]/[Pyr]
Since this is a weak acid, assume that the [Pyr] doesn't change much, and is equal to 0.200 M. The concentration of the protonated form of pyridine will be the same as the [OH-], and let both of them equal x.
So, you have 1.7 X 10^-9 = x^2/0.200
Solve for x. That will be [OH-]
2007-03-11 18:23:06 · answer #2 · answered by hcbiochem 7 · 0⤊ 0⤋
You can use the following equation in order to solve for the [OH-] concentration
[OH-]= sqrt(Kb x initial concentration)
=sqrt(1.7 x 10^-9 x .2)
[OH-]=1.84 x 10^-5 M
Hope this helps! Sorry if I made any mistakes
2007-03-11 18:24:55 · answer #3 · answered by Anonymous · 0⤊ 0⤋