HX (aq) + H2O(l)Â Â --------------------> H3O+(aq) +
X-(aq)
0.0538
                                                 Â
0Â Â Â Â Â 0.116
       Â
0.0538 -
x                                             Â
x          Â
0.116+x
Ka = x (0.116+x) / 0.0538 - x Â
3.16 x 10^-7 = x (0.116+x) / 0.0538 - x
x = 1.47 x 10^-7
[H3O+] = 1.47 x 10^-7 M