1. Balance the Equation:

The equation you provided is already balanced:

6HCl + Fe₂O₃ → 2FeCl₃ + 3H₂O

2. Calculate the Molar Mass of HCl and H₂O:

* HCl: 1.01 g/mol (H) + 35.45 g/mol (Cl) = 36.46 g/mol

* H₂O: 2.02 g/mol (H) + 16.00 g/mol (O) = 18.02 g/mol

3. Convert Grams of HCl to Moles:

* Moles of HCl = (12.0 g HCl) / (36.46 g/mol HCl) = 0.329 mol HCl

4. Use the Mole Ratio from the Balanced Equation:

The balanced equation shows a 6:3 mole ratio between HCl and H₂O. This means for every 6 moles of HCl, 3 moles of H₂O are produced.

5. Calculate the Moles of H₂O Produced:

* Moles of H₂O = (0.329 mol HCl) * (3 mol H₂O / 6 mol HCl) = 0.165 mol H₂O

6. Convert Moles of H₂O to Grams:

* Grams of H₂O = (0.165 mol H₂O) * (18.02 g/mol H₂O) = 2.97 g H₂O

Therefore, 2.97 grams of H₂O are produced when 12.0 grams of HCl react completely.