Hello!
You'll need to react 7,5 moles of Sodium with sulfuric acid to produce 3.75 moles of sodium sulfate
First of all, you need to balance the reaction. The balanced reaction is shown below (ensuring that the Law of Conservation of Mass is met on both sides):
2Na + H₂SO₄ → Na₂SO₄ + H₂
Now, all that you have to do is to use molar equivalences in this reaction applying the coefficients to calculate the moles of Sodium that you'll need:
[tex]molesNa=3,75moles Na_{2} SO_4* \frac{2 moles Na}{1 mol Na_{2} SO_4} =7,5 moles Na[/tex]
Have a nice day!
