What are the the missing reactants for the double-displacement reaction that produces PF5 and AsCl3 ?

Answer 1

...........==> 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

Answer 2

PCl3+AsF5

Answer 3

PCl5 abd AsF3

Answer 4

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