Practice question

Given: For the reaction 3A -> 2B + C, the concentration of A decreases from 0.27 M to 0.24 M in 15 seconds. What is the average rate of formation of B in mol L^{-1 s^{-1 ? Formula: Rate = -1/3 fracΔ[A]Δ t = 1/2 fracΔ[B]Δ t = fracΔ[C]Δ t. Substitution & Calculation: Δ[A] = 0.24 - 0.27 = -0.03 mol L^{-1, Δ t = 15 s . -fracΔ[A]Δ t = 2.0 × 10⁻³, so fracΔ[B]Δ t = 2/3 × 2.0 × 10⁻³= 1.33 × 10⁻³. Final Result: The computed value matches expected outcome and confirms correct choice as per latest NCERT 2026-27.