Q. During the kinetic study of the reaction 2A + B → C + D, following results were obtained: Run I: [A] = 0.1, [B] = 0.1, rate = 6.0 × 10⁻³ Run II: [A] = 0.3, [B] = 0.2, rate = 7.2 × 10⁻² Run III: [A] = 0.3, [B] = 0.4, rate = 2.88 × 10⁻¹ Run IV: [A] = 0.4, [B] = 0.1, rate = 2.40 × 10⁻² ([A], [B] in mol L⁻¹; initial rate of formation of D in mol L⁻¹ min⁻¹) Based on the above data which one of the following is correct?
A) rate = k[A][B]²
B) rate = k[A]²[B]
C) rate = k[A][B]
D) rate = k[A]²[B]²
Explanation
[Solution from source] Runs II and III: [A] fixed, [B] doubled, rate × 4, so order in B = 2. Runs I and IV: [B] fixed, [A] × 4, rate × 4, so order in A = 1. Rate = k[A][B]²; check: Run II/Run I = (3 × 4) = 12 = 7.2 × 10⁻²/6.0 × 10⁻³. Answer (1).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.