Concept:The mathematical dependence of the reaction speed on reactant concentration defines its kinetic order.
Formula:$$ \text{Rate} = k[\text{Reactant}]^{0} = k(1) = k $$
Solution:- When a reaction rate is entirely independent of the reactant concentration, it means changing the concentration has zero effect on the speed.
- Mathematically, this corresponds to the concentration term being raised to the power of zero.
- Because anything raised to the power of zero is 1, the rate stays locked at the constant value \( k \).
- This is the absolute definition of a zero order reaction.
Why other options are incorrect:In 1st, 2nd, and 3rd order reactions, the rate directly scales (linearly, quadratically, or cubically) with changes in concentration.
Quality & Fidelity Assurance:
Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.