# 1.In a closed vessel,4 moles of hydrogen & 3 moles of iodine were heated at 450K . At equilibrium, 5 moles of HI were formed.Calculate, the value of Kc. 2.Calculate the equilibrium constant , for the reaction, if one mole of phosphorous pentachloride is heated in a closed vessel of volume 10metercube. At the equilibrium , 0.40 mole of phosphorous trichloride , was found to be present.

Kamlesh Kumar
10 years ago
H2 + I2 ============= 2 HI
initialiy 4mole 3 mole 0 moles
at equlibrium (4_ x) mole (3_ x)mole 5 mole(2 x mole )

2 x =5
5
x =____ = 2.5
2
[HI]2 [ 2.5 ]2 6.25
kc=______________=_______________ = ____________= 1
[H2 ] x [I2] [2.5] x [2.5 ] 6.25

So value of Kc= 1

PCl5==============PCl3 + Cl2
1 mole 0 mole 0 mole
(1__ x) mole x mole x mole
given at equilibrium x = 0.40
so at equilibrium moles of PCl5=1_x =1_0.4 = 0.6

moles of PCl3= 0.4
moles of Cl2 =0.4

( 0.4/ 10) X (0.4/10) 0.16 X 10
KC=____________________ =__________________ =0.026
( 0.6/10) 100 X 0.60

THANKS&REGARDS
kamlesh kumar