Answer to Question #86035 in General Chemistry for thomas

Question

The colorless solid phosphorus pentachloride reacts violently with water to give a mixture of phosphoric acid and hydrochloric acid .

(a) Write a balanced chemical equation for this reaction.

_______+________--_______+_______

(b) Determine the concentration (in moles per liter) of each of the acids that result from the complete reaction of 3.57×10-2 moles of phosphorus pentachloride with enough water to give a solution volume of 806 mL.

phosphoric acid : ______ M

hydrochloric acid: _______ M

Answer 1

a) PCl₅ + 4H₂O ->H₃PO₄+5HCl

b) According to equation mole ratio n(PCl₅):n(H₃PO₄)= 1:1, then n(H₃PO₄)=n(PCl₅)=3.57*10^-2mol

c(H₃PO₄)=3.57*10^-2mol/0.806L=0.0443mol/L= 0.0443M

According to equation mole ratio n(PCl₅):n(HCl)=1:5, then n(HCl)=5*n(PCl₅)=5*3.57*10^-2=0.179mol

c(HCl)=0.179mol/0.806L=0.221mol/L=0.221M.