Answer: decreases.
- A increases
- B decreases
- C stays constant
- D becomes infinite
Correct answer: B. decreases
Explanation: As reactants are used up their concentrations fall, so the rate decreases with time.
First-order decay curve: concentration halves every t½, and that half-life is constant - a defining test for first-order kinetics.
Concept context
Study the speed of reactions and what affects it: concentration, temperature, and catalysts. Covers rate law, order of reaction, the Arrhenius equation, and reaction mechanisms step by step.