Question

A 0.0500 L solution of a 0.1000 M solution of a weak acid, HY. Ka = 1.80 x 10^-8. The solution is titrated with 0.1000 M NaOH. The pH at the equivalence point is approximately 10.20
A. Find the net ionic equation
B. Determine the pH of the original weak acid solution. (before the titration took place = initial pH)

Answer 1

A. You want the net ionic equation FOR WHAT? THE TITRATION? THE IONIZATION OF HY? THE HYDROLYSIS OF HY?

B. ............HY + H2O ==> H3O^+ + Y^
I................0.1......................0.............0
C................-x........................x..............x
E.............0.1- x.....................x...............x
Ka = (H^+)(Y^-)/(HY)
1.8E-8 = (x)(x)/(0.1-x)
Solve for x = (H3O^+) and convert to pH.

Answer 2

Thank you for your help on B !
The net ionic equation is for the titration

Answer 3

The molecular equation for the titration is as follows:
HY(aq) + NaOH(aq) ==> NaY(aq) + H2O(l)
Net ionic equation is as follows:
HY(aq) + OH^-(aq) --> Y^-(aq) + H2O(l)