Question

_______ is the order of the reaction for which rates are independent of substrate concentration.

• A. \( \text{Three} \)
• B. \( \text{Two} \)
• C. \( \text{One} \)
• D. \( \text{Zero} \)

Hint:

Zero-order reactions often occur in enzyme-catalyzed systems when the enzyme is completely saturated with substrate.

Answer 1

The Correct Option is D

Concept: The order of a reaction describes the relationship between the rate of reaction and the concentration of the reactants.
• The rate law is generally expressed as: \( \text{Rate} = k[S]^n \).
• Here, \( n \) represents the order of the reaction.

Step 1: Defining independence.
If the rate is "independent" of the concentration, it means that changing the concentration does not change the speed of the reaction. Mathematically, this means the concentration term must be raised to the power of zero.

Step 2: Application of Zero-Order Kinetics.
When \( n = 0 \), the equation becomes: \( \text{Rate} = k[S]^0 = k(1) \). Thus, for a Zero-Order reaction, the rate is constant and equal to the rate constant \( k \).