Hydrogen chloride, HCI, can be made by the reaction of phosphorus trichloride, PCl₃, with water and then boiling the HCI gas out of the solution. Calculate the mass of HCI gas that can be prepared from 15.0 g of PCl₃ and an excess of water.
PCl₃(g) + 3 H₂O(l) $\rightarrow$ 3 HCI(aq) + H₃PO₃(aq)

Question

Hydrogen chloride, HCI, can be made by the reaction of phosphorus trichloride, PCl₃, with water and then boiling the HCI gas out of the solution. Calculate the mass of HCI gas that can be prepared from 15.0 g of PCl₃ and an excess of water.
PCl₃(g) + 3 H₂O(l)

\rightarrow

3 HCI(aq) + H₃PO₃(aq)

Quizplus · Accepted Answer

First, correct the chemical formulas: PCl3 + 3 H2O → 3 HCl + H3PO3. The molar mass of PCl3 is approximately 137.33 g/mol. From the given 15.0 g of PCl3, the number of moles of PCl3 is 15.0 g / 137.33 g/mol ≈ 0.109 mol. The reaction shows that 1 mole of PCl3 produces 3 moles of HCl. Therefore, 0.109 mol of PCl3 will produce 0.109 mol × 3 = 0.327 mol of HCl. The molar mass of HCl is approximately 36.46 g/mol, so the mass of HCl gas produced is 0.327 mol × 36.46 g/mol ≈ 11.9 g.

Hydrogen Chloride, HCI, Can Be Made by the Reaction of Phosphorus