Question

hydrogen iodide decomposes to form hydrogen and iodine, like this:
2hi(g)→h₂(g)+i₂(g)
write the pressure equilibrium constant expression for this reaction.

Explanation:

Step1: Recall the formula for pressure equilibrium constant

For a general reaction \(aA(g)+bB(g)
ightleftharpoons cC(g)+dD(g)\), the pressure equilibrium constant \(K_p=\frac{P_C^c\times P_D^d}{P_A^a\times P_B^b}\), where \(P\) represents partial pressure.

Step2: Apply the formula to the given reaction

In the reaction \(2HI(g)
ightleftharpoons H_2(g)+I_2(g)\), \(a = 2\), \(c = 1\), \(d=1\). So \(K_p=\frac{P_{H_2}\times P_{I_2}}{P_{HI}^2}\)

Answer:

\(K_p=\frac{P_{H_2}\times P_{I_2}}{P_{HI}^2}\)