Pseudo-first-order reactions
Chemical Kinetics · Chemistry
Study notes
Ethyl acetate hydrolysis: rate = k[ester][H₂O]. In dilute aqueous acid, find the effective order. Step 1: [H₂O] ≈ 55.5 M, essentially constant (huge excess). Step 2: rate = (k × 55.5)[ester] = k'[ester]. Step 3: First-order plots (ln[ester] vs t) go straight → pseudo-first order. Step 4: True k = k'/55.5 — the flood hides water's role. Pseudo order is a disguise worn by excess.