How many liters of gases when magnesium is dissolved in 50 g of 39.2% sulfuric acid solution?

1. Let’s find the mass of Н2SO4 in the solution.

W = m (substance): m (solution) × 100%, hence

m (substance) = (m (solution) × W): 100%.

m (substance) = (50 g × 39.2%): 100% = 19.6 g.

1.Let’s find the amount of substance Н2SO4.

M (H2SO4) = 98 g / mol.

n = 19.6 g: 98 g / mol = 0.2 mol.

Let’s find the quantitative ratios of substances.

Mg + H2SO4 = MgSO4 + H2.

For 1 mol of H2, there is 1 mol of H2SO4.

The substances are in quantitative ratios of 1: 1.

The amount of substance H2 and H2SO4 are equal.

n (H2) = n (H2SO4) = 0.2 mol.

Let’s find the volume of H2.

V = n Vn, where Vn is the molar volume of the gas equal to 22.4 l / mol.

V = 0.2 mol × 22.4 L / mol = 4.48 L.

Answer: 4.48 liters.