How many liters of hydrogen are formed when sodium interacts with 20 g of a 20% sulfuric acid solution.

Given:
m solution (H2SO4) = 20 g
ω (H2SO4) = 20%
Vm = 22.4 l / mol

To find:
V (H2) -?

Decision:
1) 2Na + H2SO4 => Na2SO4 + H2 ↑;
2) m (H2SO4) = ω (H2SO4) * m solution (H2SO4) / 100% = 20% * 20/100% = 4 g;
3) M (H2SO4) = Mr (H2SO4) = Ar (H) * N (H) + Ar (S) * N (S) + Ar (O) * N (O) = 1 * 2 + 32 * 1 + 16 * 4 = 98 g / mol;
4) n (H2SO4) = m (H2SO4) / M (H2SO4) = 4/98 = 0.04 mol;
5) n (H2) = n (H2SO4) = 0.04 mol;
6) V (H2) = n (H2) * Vm = 0.04 * 22.4 = 0.896 l.

Answer: The volume of H2 is 0.896 liters.