Autocatalytic reactions exhibit accelerating then decelerating rates over time

Steps:

• Autocatalytic reactions involve a product that speeds up the reaction, so initial rate is low due to scarce catalyst.
• As product accumulates, the rate increases rapidly because more catalyst is available.
• The rate reaches a maximum when product concentration peaks relative to reactants.
• Eventually, reactant depletion causes the rate to decline.

Why C is correct:

• Curve C depicts a rate that starts low, rises to a peak, and then falls, aligning with the rate law where rate ∝ [reactant][product], leading to a bell-shaped profile.

Why the others are wrong:

• A shows a constant rate, typical of zero-order kinetics, not autocatalysis.
• B shows a steadily decreasing rate, characteristic of simple first-order decay without catalysis.
• D shows continuous increase, like exponential growth, ignoring reactant depletion.

Final answer: C