An excess of hydrochloric acid solution was added to a solution of sodium sulfite weighing 252 g with a mass fraction of 5%.

| February 26, 2021 | education

An excess of hydrochloric acid solution was added to a solution of sodium sulfite weighing 252 g with a mass fraction of 5%. Calculate the volume under normal conditions of the evolved gas.

Mass fraction of a substance is calculated by the formula:

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

m (substance) = (252 × 5): 100% = 12.6 g.

Find the amount of sodium sulfite substance by the formula:

n = m: M.

M (Na2SO3) = 46 + 32 + 48 = 126 g / mol.

n = 12.6 g: 126 g / mol = 0.1 mol.

Let’s compose the reaction equation. Let’s find in what quantitative ratios the substances are.

Na2SO3 + 2HCl = 2NaCl + SO2 + H2O.

Substances are in quantitative ratios 1: 1.

Therefore, their amount of substance will be equal.

n (SO2) = n (Na2SO3) = 0.1 mol.

Let’s find the volume of the gas.

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

V = 0.1 mol × 22.4 L / mol = 2.24 L.

Answer: V = 2.24 liters.



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