A substance X decomposes via two parallel pseudo-first-order pathways to Y and Z in a large excess of solvent W.
The activation energies are Ea₁ = 50 kJ/mol and Ea₂ = 70 kJ/mol. At 300 K, k₁ = 3k₂ . Which of the following is/are correct?

Question

A substance X decomposes via two parallel pseudo-first-order pathways to Y and Z in a large excess of solvent W.

The activation energies are Ea₁ = 50 kJ/mol and Ea₂ = 70 kJ/mol. At 300 K, k₁ = 3k₂ . Which of the following is/are correct?

TestHub · Accepted Answer

Concept:

Parallel reactions, Arrhenius equation, Effective activation energy $(E_{eff} = \frac{k _{1} E _{a 1} + k _{2} E _{a 2}}{k _{1} + k _{2}})$ , Yield analysis.

Solution:

• For parallel reactions X → Y and X → Z, k_net = k₁ + k₂ . (A) is correct.

• [Y] / [Z] = k₁ / k₂ . Since k values are constants at a fixed T, the ratio is independent of time. (D) is correct.

• Higher E_a means the reaction is more sensitive to temperature. Since Ea₂ > Ea₁ , k₂ increases more rapidly with T than k₁ . Thus, the yield of Z increases. (B) is correct.

Chemistry - Chemical Kinetics Question with Solution | TestHub

Options:(select one or more)

Doubts & Discussion