Question

What is the percent yield of a reaction in which 217.8 g of phosphorus trichloride reacts with excess water to form 125.2 g of HCl and aqueous phosphorous acid (H3PO3)?

Answer 1

Balanced equation is

PCl3 + 3H2O ------> 3HCl + H3PO3

number of moles of PCl3 = 217.8g / 137.33 g/mol = 1.59 mole

from the balanced equation we can say that

1 mole of PCl3 produces 3 mole of HCl so

1.59 mole of PCl3 will produce 4.77 mole of HCl

1 mole of HCl = 36.46 g

so 4.77 mole of HCl = 173.9 g

Therefore, theoretical yield of HCl = 173.9 g

percent yield = (actual yield / theoretical yield)*100

percent yield = (125.2g / 173.9)*100 = 72.0 %

Therefore, percent yield = 72.0 %