@Edward W. presents the correct answer, but I thought you might want an explanation as to how one might arrive at that answer.
Write the balanced equation:
2H2 + O2 ==> 2H2O
26.1 g H2O x 1 mol H2O/18 g = 1.45 moles H2O produced
23.0 g O2 x 1 mol O2/32 g = 0.719 moles O2 used
Since the mole ratio of H2 to O2 is 2:1, this means 0.719 x 2 = 1.44 moles H2 would be used.
1.44 moles H2 x 2 g/mol = 2.88 g H2 were used