Question

When heating PCI, then it decompose PCl, and
Cl, in form of gas, The vapour density of gas
mixture is 70.2 and 57.9 at 200° C and 250°C.
The degree of dissociation of PCl, at 200°C and
250°C is
(1) 48.50% & 80% (2) 60% & 70%
(3) 70% & 80% 6 (4) 80% & 90%​

Answer 1

Answer:

48.50% and 80%

We know that when PCl5 is heated it decomposes to give PCl

3

and Cl

2

PCl

5

→PCl

3

+Cl

2

Given,

The vapour density at equilibrium at 200

0

C and 250 C.The initial Vapour Density at both the temperature MPCl5/2

therefore,initial V.D.=(31+5×35.5)/2=104.5

V..D. at equilibrium at 200

0

C=70.2(given)

total moles initial

total mole at equilibrium

=1+α=

V.D. at equilibrium

initial V.D.

1+α=

70.2

104.5

=1.485

α=0.485

∴%α=48.5%

At 250

ο

C

1+α=

57.9

104.25

=1.8

α=0.80

∴%α=80%