A sample of HI(g) is placed in flask at a pressure of 0.2 atm. At equilibrium the partial pressure of HI(g) is 0.04 atm. What is Kp for the given equilibrium?
2HI (g) ⇌H2 (g) + I2 (g)
Partial pressure of HI = 0.04 atm
sum of partial pressures = total pressure,
thus,
P(H2)+P(I2)= P – P(HI)
Where,
P is total pressure = 0.2 atm
P(H2) is Partial pressure of H2 = x
P(I2) is Partial pressure of I2= x
P(HI) is Partial pressure of HI = 0.04 atm
∴ x + x = 0.2 – 0.04
= 0.16
i.e, x = 0.08 atm
Kp=
= = 4