Hydrogen chloride decomposes to form hydrogen and chlorine, like this. Also, a chemist finds that at a certain temperature the equilibrium mixture of hydrogen chloride, hydrogen, and chlorine has the following composition: Compound Pressure at equilibrium HCL 84.4 atm H2 77.9 atm Cl2 54.4 atm
Calculate the value of the equilibrium constant for this reaction.

0.595

Explanation:

Let's consider the decomposition of hydrogen chloride.

2 HCl(g) ⇄ H₂(g) + Cl₂(g)

The pressure equilibrium constant (Kp) is equal to the product of the partial pressure of the products raised to their stoichiometric coefficients divided by the product of the partial pressure of the reactants raised to their stoichiometric coefficients.

Kp = pH₂ × pCl₂ / pHCl²

Kp = 77.9 × 54.4 / 84.4²

Kp = 0.595