Hydrochloric acid was added to 400 g of 10.6% Na2Co3 sodium carbonate solution. Find the volume of gas?

We compose the reaction equation and arrange the coefficients:
Na2CO3 + 2HCl = 2NaCl + H2O + CO2.
1) Find the mass of the sodium carbonate solute in its solution. To do this, we multiply the mass fraction of the substance by the mass of the solution and divide by one hundred percent: 10.6 * 400/100 = 42.4 g.
2) Find the amount of sodium carbonate substance: 42.4 / 106 = 0.4 mol.
3) The amount of carbon dioxide substance is equal to the amount of sodium carbonate substance (according to the reaction equation).
4) Find the volume of carbon dioxide. To do this, we multiply the amount of gas substance by the molar volume: 0.4 * 22.4 = 8.96 liters – the answer.