Find the mass of a potassium hydroxide solution with a mass fraction of alkali of 4% required for the reaction

Find the mass of a potassium hydroxide solution with a mass fraction of alkali of 4% required for the reaction with carbon dioxide, if the result is an average salt with a mass of 27.6 g.

First, we compose the reaction equation.
2KOH + CO2 = K2CO3 + H2O
Using the reaction equation, we find the mass of potassium hydroxide.
M (KOH) = 39 + 1 + 16 = 56 g / mol.
M (K2CO3) = 39 × 2 + 12 + 16 × 3 = 138 g / mol.
X g KOH – 27.6 g K2CO3
2 × 56 g / mol KOH – 138 g / mol K2CO3
X = 2 × 56 × 27.6 ÷ 138 = 22.4 g KOH
This means that the mass of potassium hydroxide is 22.4 grams.
Answer: m (KOH) = 22.4 g.