Question

In which of the following equilibria, Kp and Ke are NOT equal?

• A. PCl5(g) ⇌ PCl3(g) + Cl2(g)
• B. H2(g)+I2(g) ⇌ 2HI(g)
• C. CO(g) +H2O(g) ⇌ CO2(g) +H2(g)
• D. 2BrCl(g) ⇌ Br2(g) + Cl2(g)

Answer 1

Answer: (A)

PCl5(g) ⇌ PCl3(g) + Cl2(g)

Answer 2

- $K_p = K_c(RT)^{\Delta n}$, where $\Delta n = \text{moles of gas products} - \text{moles of gas reactants}$.
- For equilibrium (4), $\Delta n \neq 0$, hence $K_p \neq K_c$.