What is the volume of 2.0M H2SO4 (aq) that would neutralize 25 mL of 4.0M NaOH (aq)?

H2SO4 + 2NaOH ==> Na2SO4 + 2H2O

mols NaOH = M x L = 4.0 x 0.025 = 0.100
mols H2SO4 = 1/2 that or 0.050
M H2SO4 = mols/L. You know mols and M, solve for L.