Calculate the mass of a 15% hydrochloric acid solution that is required to dissolve 2.15 g of Fe (OH) 3.

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

Fe (OH) 3 + 3HCl = FeCl3 + 3H2O.

2. Find the chemical amount of iron hydroxide:

n (Fe (OH) 3) = m (Fe (OH) 3) / M (Fe (OH) 3) = 2.15 g / 107 g / mol = 0.02 mol.

3. According to the reaction equation, we find the chemical amount, and then the mass of hydrochloric acid:

n (HCl) = n (Fe (OH) 3) * 3 = 0.02 mol * 3 = 0.06 mol.

m (HCl) = n (HCl) * M (HCl) = 0.06 mol * 36.5 g / mol = 2.2 g.

4. Find the mass of the hydrochloric acid solution:

m (solution) = m (HCl) * 100% / ω (HCl) = 2.2 g * 100% / 15% = 14.67 g.

Answer: m (solution) = 14.67 g.