How much by volume will 98% sulfuric acid (p = 1.8 g / ml) be needed to obtain 5.6 liters

How much by volume will 98% sulfuric acid (p = 1.8 g / ml) be needed to obtain 5.6 liters of sulfur (IV) oxide when interacting with mercury?

Given:
ω (H2SO4) = 98%
ρ solution (H2SO4) = 1.8 g / ml
V (SO2) = 5.6 l

Find:
V solution (H2SO4) -?

Solution:
1) 2H2SO4 + Hg => HgSO4 + SO2 ↑ + 2H2O;
2) n (SO2) = V (SO2) / Vm = 5.6 / 22.4 = 0.25 mol;
3) n (H2SO4) = n (SO2) * 2 = 0.25 * 2 = 0.5 mol;
4) m (H2SO4) = n (H2SO4) * M (H2SO4) = 0.5 * 98 = 49 g;
5) m solution (H2SO4) = m (H2SO4) * 100% / ω (H2SO4) = 49 * 100% / 98% = 50 g;
6) V solution (H2SO4) = m solution (H2SO4) / ρ solution (H2SO4) = 50 / 1.8 = 27.8 ml.

Answer: The volume of the H2SO4 solution is 27.8 ml.