Find the mass of 4% calcium hydroxide solution reacted with sulfur oxide 4.

Given:
ω (Ca (OH) 2) = 4%

To find:
m (Ca (OH) 2) -?

1) Ca (OH) 2 + SO2 => CaSO3 + H2O;
2) Let V (SO2) = 2.24 l;
3) n (SO2) = V / Vm = 2.24 / 22.4 = 0.1 mol;
4) n (Ca (OH) 2) = n (SO2) = 0.1 mol;
5) m (Ca (OH) 2) = n * M = 0.1 * 74 = 7.4 g;
6) m solution (Ca (OH) 2) = m * 100% / ω = 7.4 * 100% / 4% = 185 g.

Answer: The mass of the Ca (OH) 2 solution is 185 g.