What volume of hydrogen can be obtained by the interaction of 0.25 mol of magnesium with an excess of dilute sulfuric acid?

We write the reaction equation:
Mg + H2SO4 = H2 ↑ + MgSO4
In the reaction equation, magnesium and hydrogen face the same coefficients. This means that their amounts of substance are also equal, i.e.:
n (H2) = n (Mg) = 0.25 mol
V (H2) = n (H2) ⋅ Vm = 0.25 ⋅ 22.4 = 5.6 mol

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