Phosphorous trichloride, a precursor for the manufacture of certain pesticides a
ID: 609089 • Letter: P
Question
Phosphorous trichloride, a precursor for the manufacture of certain pesticides and herbicides, can be produced by the reaction of phosphorous and chlorine: P4 + 6 Cl2 right arrow 4 PCl3 When 20.5 g of P4 and 20.5 g of cl2 are reacted, how many moles of PCl3 can be produced? When 55 g of Cl2 are reacted with 25 g of P4 how many grams of PCl3 can be produced? Which reactant is in excess? In a reaction vessel, 15 mol of P4 and 35 mol oc Cl2 react. Determine which substances will be present in the container after the reaction goes to completion and how many moles of each.Explanation / Answer
number of moles of phosphorus=20.5/124=0.165;...number of moles of chlorine=20.5/71=0.288....For 0.288 moles of chlorine (0.288/6)=0.048 moles of phosphorus is required. and moles of PCl3 produced=(4/6)*0.288=0.192.......(b)number of moles of phosphorus=25/124=0.20;...number of moles of chlorine=55/71=0.774....For 0.774 moles of chlorine (0.774/6)=0.129 moles of phosphorus is required. and moles of PCl3 produced=(4/6)*0.774=0.516....Here phosporous is in excess since (0.20-0.129) moles are left over...(c)for 35 moles of Cl2 number of moles of phosporous required=35/6=5.833..So after reaction phosporous left=15-5.833=9.17 moles, PCl3 present=(4/6)*35=23.32 moles