Question

Consider the balanced equation.


PCl3 + 3H2O Right arrow. H3PO3 + 3HCl


What is the percent yield of HCl if 42.0 g of HCl are produced from the reaction of 62.0 g of PCl3?
Use Percent yield equals StartFraction actual yield over theoretical yield EndFraction times 100..
28.4%
72.8%
85.0%
93.5%

Answer 1

Molar masses: PCl3 = 137.33 g·mol−1, HCl = 36.46 g·mol−1.

Moles PCl3 = 62.0 / 137.33 = 0.4514 mol
Theoretical moles HCl = 3 × 0.4514 = 1.3542 mol
Theoretical mass HCl = 1.3542 × 36.46 = 49.4 g

Percent yield = (actual / theoretical) × 100 = (42.0 / 49.4) × 100 = 85.0%

Answer: 85.0%