The balanced equation for the reaction between Na and H₂SO₄ is as follows;
2Na + H₂SO₄ ---> Na₂SO₄ + H₂
Stoichiometry of Na to H₂SO₄ is 2:1
the molar concentration of H₂SO₄ is 6.0 M
This means that in 1 L of H₂SO₄ - there are 6.0 mol of H₂SO₄
Therefore in 750 mL -
Number of H₂SO₄ moles reacted - 4.5 mol
According to stoichiometry,
1 mol of H₂SO₄ reacts with 2 mol of Na
Therefore 4.5 mol reacts with 2x4.5= 9 mol of Na
Mass of Na reacted - 9 mol x 23 g/mol = 207 g of Na is required