Consider the balanced equation. PCl sub 3 plus 3 cap h sub 2 cap o rightarrow cap h sub 3 PO sub 3 plus 3 HCl What is the percent yield of HCl if 42 point 0 g of HCl are produced from the reaction of 62 point 0 g of PCl sub 3 ? Use percent Yield is equal to Actual yield over Theoretical yield times 100

The balanced equation shows that 1 mol of PCl₃ produces 3 mol of HCl. Using molar masses of 137.33 g/mol for PCl₃ and 36.46 g/mol for HCl, 62.0 g of PCl₃ can theoretically produce about 49.4 g of HCl. The percent yield is (42.0 g ÷ 49.4 g) × 100 ≈ 85.0%, so the correct choice is 85.0 percent.

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