Three moles of `PCl_(5)` , three moles of `PCl_(3)` and two moles of `Cl_(2)` are taken in a closed vessel . If at equilibrium the vessel has 1.5 moles of `PCl_(5)` , the number of moles of `PCl_(3)` present in it is

Options

A. 6
B. 4.5
C. 5
D. 3

Answer

B

Explanation

`{:(PCl_(s(g))hArrPCl_(3(g))_Cl_(2(g))),("3 3 2 (Initially)"),((3-x)" "(3+x)" "(2+2)" (At equilibrium)"):}`
Given that `(3-x)=1.5thereforex=1.5`
Therefore no. of moles of `PCl_(3(g))` present is
`=3+1.5=4.5`