What is the percent yield of a reaction in which 200. g of phosphorus trichloride reacts with excess water to form 138 g of HCl and aqueous phosphorous acid (H3PO3)?

2 answers

write the equation
figure the moles of phosphorus trichloride
the equation tells you how many moles of HCl to expect
convert that to grams
divide 138 by the expected mass * 100%
calculate mass