[licamine]

Consider a solution from a hypothetic acid H₂X 0.010 M and calculate:
a) The pH of this solution, admitting the ionization of a single proton;
b) The pH of this solution, admtting both protons ionize completely;
If in an experiment it is determined that the pH of a solution 0.050 M from this acid is 1.26:
c) Compare the strenghts of acids H₂X and HX^- ;
d) Would a solution from NaHX be acidic, basic ou neutral?

My doubt is in items c) and d). Considering the first deprotonation to be complete, the pH would be 1.30, thus the other 10^0.04 M would be due to the deprotonation of HX^-. I followed that and got to a constant Ka2=6.04x10^-3. The ionization percentile would be of about 10%: not strong like the first deprotonation but not such a weak acid. Should  the first deprotonation  be considered as complete straight away, as I did? How can I determine the pH of a NaHX solution from this? I figured it would be acidic, since HX^- has quite a high Ka, but I'm not sure.
Thank you very much!