1. 2BrCl_((g)) ⇌ Br_(2(g)) + Cl_(2(g)) 2. PCl_(5(g)) ⇌ PCl_(3(g)) + Cl_(2(g)) 3. H_(2(g)) + I_(2(g)) ⇌ 2HI_((g)) 4. CO_((g)) + H₂O_((g)) ⇌ CO_(2(g)) + H_(2(g))

Answer: 2. PCl_(5(g)) ⇌ PCl_(3(g)) + Cl_(2(g)) Key idea: K_p=K_c(RT)^(Δ n_g) . They are equal only when Δ n_g=0 . 2BrCl⇌ Br₂+Cl₂ : Δ n_g=0 . PCl₅⇌ PCl₃+Cl₂ : Δ n_g=2-1=1 , so K_p≠ K_c . H₂+I₂⇌2HI : Δ n_g=0 . CO+H₂O⇌ CO₂+H₂ : Δ n_g=0 . Option 2.

Topic: Law of chemical equilibrium, Kp and Kc· Equilibrium

In which of the following equilibria, K_p and K_c are NOT equal?

1. \(2BrCl_{(g)} \rightleftharpoons Br_{2(g)} + Cl_{2(g)}\)

2. \(PCl_{5(g)} \rightleftharpoons PCl_{3(g)} + Cl_{2(g)}\)

3. \(H_{2(g)} + I_{2(g)} \rightleftharpoons 2HI_{(g)}\)

4. \(CO_{(g)} + H_2O_{(g)} \rightleftharpoons CO_{2(g)} + H_{2(g)}\)

Doubtly Asked 30 Oct 2026 NEET UG 2024 Practice test neet Save WhatsApp Report

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Answer: 2. \(PCl_{5(g)} \rightleftharpoons PCl_{3(g)} + Cl_{2(g)}\)

Key idea: \(K_p=K_c(RT)^{\Delta n_g}\). They are equal only when \(\Delta n_g=0\).

\(\mathrm{2BrCl\rightleftharpoons Br_2+Cl_2}\): \(\Delta n_g=0\).
\(\mathrm{PCl_5\rightleftharpoons PCl_3+Cl_2}\): \(\Delta n_g=2-1=1\), so \(K_p\ne K_c\).
\(\mathrm{H_2+I_2\rightleftharpoons2HI}\): \(\Delta n_g=0\).
\(\mathrm{CO+H_2O\rightleftharpoons CO_2+H_2}\): \(\Delta n_g=0\).

Option 2.

Doubtly AI · 30 Oct 2026 AI-generated · not yet verified Report

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In which of the following equilibria, K_p and K_c are NOT equal?

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