PCl5, PCl3 and Cl2 are at equilibrium at 500 K in a closed container and their concentrations are 0.8×10-3 mol L-11.2×10-3 mol L-1 and 1.2×10-3 mol L-1, respectively. The value of Kc for the reaction

PCl5(g)PCl3(g)+Cl2(g) will be

(1) 1.8×103 mol L-1

(2) 1.8×103

(3) 1.8×10-3 mol1 L

(4) 0.55×104

Hint: Kc=[PCl3][Cl2][PCl5]
 
Step 1:
 
For the reaction, PCl5(g)PCl3(g)+Cl2(g)
The given values are as follows:
At 500 K in a closed container, [PCl5]=0.8×10-3 mol L-1
 
[PCl3]=1.2×10-3 mol L-1
 
[Cl2]=1.2×10-3 mol L-1
 
Step 2:
 
Kc=[PCl3][Cl2][PCl5]=(1.2×10-3)×(1.2×10-3)(0.8×10-3)=1.8×10-3