Hydrogen and chlorine react to form hydrogen chloride, like this:
H2(g) + Cl2(g) → 2 HCl(g)
Also, a chemist finds that at a certain temperature the equilibrium mixture of hydrogen, chlorine, and hydrogen chloride has the following composition:

compound pressure at equilibrium
HCl 18.0 atm
H2 25.4 atm
Cl2 46.4 atm

Calculate the value of the equilibrium constant Kp for this reaction. Round your answer to significant digits.

the value of the equilibrium constant Kp for this reaction is 0.275

Explanation:

Step 1: Data given

Pressure HCl at the equilibrium = 18.0 atm

Pressure H2 at the equilibrium = 25.4 atm

Pressure Cl2 at the equilibrium = 46.4 atm

Step 2: The balanced equation

H2(g) + Cl2(g) → 2 HCl(g)

Step 3: Calculate the value of the equilibrium constant Kp for this reaction

Kp = (pHCl)² / (pH2*pCl2)

Kp = 18.0² / (25.4 * 46.4)

Kp = 324 / 1178.56

Kp = 0.275

the value of the equilibrium constant Kp for this reaction is 0.275