In: Chemistry
Part A Determine the [H3O+] of a 0.250 M solution of formic acid. Express your answer using two significant figures.
Part B
Determine pH of this solution of formic acid.
Express your answer to two decimal places.
HCOOH + H2O ----------> HCOO- + H3O+
I 0.25 0 0
C -x +x +x
E 0.25-x +x +x
Ka = [HCOO-][H3O+]/[HCOOH]
1.77*10^-4 = x*x/0.25-x
1.77*10^-4 *(0.25-x) = x^2
x = 0.00656
[H3O+] = x = 0.00656M
PH = -log[H3O+]
= -log0.00656
= 2.183