P3.2.1 A molecule, A, reacts to form either B or C with first-order rate constants k₁ and k₂, respectively. That is, and so d[A] dt = -(k₁ + k₂)[A], [A] = [A]oe (k+k2)1 where [A] is the initial concentration of A. The product concentrations (starting from 0) increase in the ratio [B]/[C] = k₁/k2 and conservation of matter requires [B] + [C] = [A] - [A]. Therefore, [B] = [C] = k₁ k₁ + k₂ k₂ [A]0 (1-e-(k₁+2)) - [A]0 (1 − e−(k₁+k2)1) k₁ + k₂ For a reaction with k₁ = 300 s¹ and k₂ = 100 s¹, plot the concentrations of A, B and C against time given an initial concentration of reactant [A] = 2.0 mol dm³.

Fig: 1