Calculate the mass of a 20% sodium hydroxide solution in which 6 g of silicon oxide (IV) can be dissolved.

1. Let’s compose the equation of the chemical reaction:

2NaOH + SiO2 = Na2SiO3 + H2O.

2. Find the chemical amount of silicon oxide:

n (SiO2) = m (SiO2) / M (SiO2) = 6 g / 60 g / mol = 0.1 mol.

3. Using the reaction equation, we find the chemical amount of sodium hydroxide, and then its mass:

n (NaOH) = n (SiO2) * 2 = 0.1 mol * 2 = 0.2 mol.

m (NaOH) = n (NaOH) * M (NaOH) = 0.2 mol * 40 g / mol = 8 g.

4. Find the mass of the sodium hydroxide solution:

m (solution) = m (NaOH) * 100% / ω (NaOH) = 8 g * 100% / 20% = 40 g.

Answer: m (solution) = 40 g.