Q. Given the reaction between 2 gases represented by A₂ and B₂ to give the compound AB(g): A₂(g) + B₂(g) ⇌ 2AB(g). At equilibrium, the concentration of A₂ = 3.0 × 10⁻³ M, of B₂ = 4.2 × 10⁻³ M and of AB = 2.8 × 10⁻³ M. If the reaction takes place in a sealed vessel at 527°C, then the value of Kc will be
A) 2.0
B) 1.9
C) 0.62
D) 4.5
Explanation
[Solution from source] Kc = [AB]²/([A₂][B₂]) = (2.8 × 10⁻³)²/(3.0 × 10⁻³ × 4.2 × 10⁻³) = 7.84 × 10⁻⁶/1.26 × 10⁻⁵ ≈ 0.62. The temperature is not needed, since Kc is computed directly from concentrations. Answer (3).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.