Chemistry Reaction Kinetics UHS 2022
PMDC Verified Question 27 of 80
What is the overall order of this rate equation? Rate = \( k[\text{H}_{2}][\text{NO}_{2}]^{2} \)
A
1
B
3
C
2
D
4
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option B: 3
Concept:

The overall order of a chemical reaction is defined as the mathematical sum of the individual powers (exponents) to which the concentration terms are raised in the rate law.

Formula:

$$ \text{Overall Order} = m + n $$

Solution:

  • Examine the rate law: \( \text{Rate} = k[\text{H}_{2}]^{1}[\text{NO}_{2}]^{2} \).
  • The exponent for \( [\text{H}_{2}] \) is 1.
  • The exponent for \( [\text{NO}_{2}] \) is 2.
  • Summing the exponents gives: \( 1 + 2 = 3 \).
  • Therefore, it is a third-order reaction overall.


Why other options are incorrect:

Option A is just the order w.r.t hydrogen. Option C is just the order w.r.t nitrogen dioxide. Option D miscalculates basic addition.

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.

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