The equilibrium constant for the reaction 2SO2 + O2 ⇋ 2 SO3 is 900 atm−1 at 800K. A mixture containing SO3 and O2 having initial pressures of 1atm and 2atm is heated to equilibrate. The partial pressure of O2at equilibrium will be
Let partial pressure of SO2= p1and partial pressure of O2= p2and partial pressure of SO3=p3
K<p = (p1)2× (p2)/ (p3)2=x2 (2+x/2)/ (1−x)2=1/900
AsKpfor this reaction is very small, x << 1.
Taking 2+x/2 as x and (1−x) as x and solving for x, we get
X = 0.0236
Hence, at equilibrium, partial pressure of SO3= 1−X=0.9764atm,
Partial pressure of SO2= x = 0.0236atm
And Partial pressure of O2= 2+x/2=2.0118atm