the balanced equation for the acid-base reaction is as follows;
2NaOH + H₂SO₄ --> Na₂SO₄ + 2H₂O
stoichiometry of NaOH to H₂SO₄ is 2:1
this means that for complete neutralisation 2 mol of NaOH reacts with 1 mol H₂SO₄
number of NaOH moles reacted = 3.0 M /1000 x 3.4 = 0.0102 mol
Number of H₂SO₄ moles reacted = 0.0102 /2 = 0.0051 mol
Number of H₂SO₄ moles in 300.0 mL - 0.0051 mol
therefore in 1 L solution -0.0051/300 x 1000= 0.017 mol
concentration is number of moles in 1 L solution
Concentration of H₂SO₄ is 0.017 M