Pseudo First-Order Condition

$$\text{Rate} = k' \cdot [A][B] \approx k \cdot [A] \qquad k = k' \cdot [B]$$

Concept: Occurs when a second-order reaction behaves as a first-order reaction because one of the reactants is present in massive excess (e.g., hydrolysis in water).

Notation:

• $$k'$$ = True second-order rate constant;
• $$k$$ = Pseudo-first-order rate constant;
• $$[B]$$ = Excess reactant concentration (virtually constant).