2.24 liters of carbon dioxide was passed through a solution weighing 40 g with a mass fraction of sodium hydroxide

2.24 liters of carbon dioxide was passed through a solution weighing 40 g with a mass fraction of sodium hydroxide of 10%. Mass fraction of salt in the resulting solution (in%) is

2NaOH + CO2 = Na2CO3 + H2O
Na2CO3 + H2O + CO2 = 2NaHCO3
CO2 is in excess, so the 2nd reaction is in progress
m (NaOH) = w * m (solution) = 0.1 * 40 = 4 g
n (NaOH) = m \ M = 4 \ 40 = 0.1 mol
n (CO2) = V \ Vm = 2.24 \ 22.4 = 0.1 mol
m (CO2) = nM = 0.1 * 44 = 4.4 g
n (Na2CO3) = 0.1: 2 = 0.05 mol
n (NaHCO3) = 0.1 mol
m (NaHCO3) = nM = 0.1 * 84 = 8.4 g
m (solution) = m (CO2) + m solution NaOH = 4.4 + 40 = 44.4 g
w (NaHCO3) = m (in-islands) \ m (solution) = 8.4 \ 44.4 = 0.189 (18.9%)
Answer: 18.9%