In which of the following gaseous reaction, the value of Kp will be equal to Kc — Chemical Equilibrium Chemistry Question

💡 Solution & Explanation

# Solution: When $K_p = K_c$ The relationship between $K_p$ and $K_c$ is: $$K_p = K_c(RT)^{\Delta n}$$ where $\Delta n = $ (moles of gaseous products) − (moles of gaseous reactants) **For $K_p = K_c$, we need:** $$(RT)^{\Delta n} = 1$$ This occurs only when $\Delta n = 0$ **Therefore, the reaction must have equal moles of gas on both sides.** ## Why Option A is Correct Without seeing the specific options, Option A must show a reaction where: - Number of moles of gaseous products = Number of moles of gaseous reactants **Common examples that satisfy this:** - $H_2(g) + I_2(g) \rightleftharpoons 2HI(g)$ → $\Delta n = 2 - 2 = 0$ ✓ - $N_2(g) + O_2(g) \rightleftharpoons 2NO(g)$ → $\Delta n = 2 - 2 = 0$ ✓ - $CO(g) + H_2O(g) \rightleftharpoons CO_2(g) + H_2(g)$ → $\Delta n = 2 - 2 = 0$ ✓ ## Why Other Options Are Wrong Any reaction with $\Delta n \neq 0$ will have $K_p \neq K_c$: - Synthesis reactions (fewer product moles) have $\Delta n < 0$ - Decomposition reactions (more product moles) have $\Delta n > 0$