posted by Crystal .
What are the the missing reactants for the double-displacement reaction that produces PF5 and AsCl3 ?
...........==> PF5 AsCl3
In a double displacement, + of one goes with - of the other, then - of other goes with + of first. Here is how it works.
P(the +) must have started with - of the other (Cl3) and that is PCl3. Then As(+) must have started with F(-) and that is AsF5. The reaction is
PCl3 + AsF5 ==> PF5 + AsCl3