The degree of dissociation is 0.4 at 400 K and 1.0 atm for the gaseous reaction. `PCl_(5) hArr PCl_(3) + Cl_(2)`. Assuming ideal behaviour of all the gases, calculate the density of equilibrium mixture at 400 K and 1.0 atmpshere. (Atomic mass of P = 31.0 and Cl = 35.5)

Options

A. 7.39 g/L
B. 3.54 g/L
C. 6.92 g/L
D. 4.53 g/L

Answer

D

Explanation

`{:(PCl_(5),hArr,PCl_(3),+,Cl_(2),),(1,,0,,0,"initial mole"),(1-0.4,,0.4,,0.4,"mole at eqilibrium"):}`
Total mole at equilibrium `= 1 - 0.4 + 0.4 + 0.4 = 1.4`
`("Normal " m_(PCl_(5)))/("Observed " m_(PCl_(5))) = 1+ alpha = 1.4 " observed " m_(PCl_(5)) = (208.5)/(1.4)`
From PV `= (w)/(m) RT` at equilibrium , `(w)/(v) = (P m)/(R T) = (1 xx 208.5)/(1.4 xx 0.082 xx 400) = 4.53 g`/litre