check answer oh ph chem?

Question

give me the answer so i can check my work
Calculate the pH after 0.029 mol HCl is added to 1.00 L of
0.100 M sodium propanoate (NaC3H5O2)(HC3H5O2, Ka= 1.3 10-5)

Calculate the pH after 0.020 mol NaOH is added to 1.00 L of 0.100 M sodium propanoate (NaC3H5O2)

Calculate the pH after 0.020 mol NaOH is added to 1.00 L 0.100 M HC3H5O2 and 0.100 M NaC3H5O2

Calculate the solubility of each of the following compounds in moles per liter. Ignore any acid-base properties.
(a) Hg2Cl2, Ksp = 1.1 10-18 (Hg22+ is the cation in solution.)
mol/L

Answer 1

I've already showed you how to do these.

For the solubility, go back to the question you asked for Ksp equillibria and see that Ksp=1^1*2^2*s^(1+2)=4s^3 =>
s= 8.25*10^-19 M

For HCl to the buffer
pH=4.63

For NaOH to sodium propanoate
pH=12.6

For NaOH to the buffer
pH=5.06

Answer 2

Ya there all right. Way to go =]

Answer 3

I have no random clue whatsoever.