Assertion (A): For complex reactions, order of reaction is given by the fast step.
Reason (R): Order of reaction is determined experimentally.
Reason (R): Order of reaction is determined experimentally.
Show Hint
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true but R is not the correct explanation of A.
- A is true but R is false.
- A is false but R is true.
The Correct Option is D
Solution and Explanation
The order of a complex (multi-step) reaction is determined by its rate-determining step, not by all steps collectively.
Step 2: Analysis
The Assertion is false: for complex reactions, the overall order is determined by the slowest step (the rate-determining step), not the fast step. The slow step is the bottleneck and dictates the overall rate law. The Reason is true: the overall order of a reaction is always determined experimentally by measuring how the rate changes with concentration, and it cannot be simply derived from the balanced equation for complex mechanisms.
Step 3: Conclusion
The Assertion is incorrect (it should be ``slow step,'' not ``fast step''), but the Reason is a correct statement about experimental determination.
Final Answer: (D)
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Top CBSE CLASS XII Order of reaction Questions
- Write IUPAC names of the following coordination entities:
(a) \( [Fe(en)_2Cl_2]^+ \)
(b) \( [Co(NH_3)_4(H_2O)Br]SO_4 \)
(c) \( [Ni(CN)_4]^{2- \)
} Write IUPAC names of the following coordination entities:
(a) \( [Fe(en)_2Cl_2]^+ \)
(b) \( [Co(NH_3)_4(H_2O)Br]SO_4 \)
(c) \( [Ni(CN)_4]^{2-} \)- Assertion (A): Order of reaction is applicable to elementary as well as complex reactions.
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- Following reaction takes place in one step:
\(2A + B \rightarrow 2C\)
How will the rate of above reaction change if the volume of the reaction vessel is decreased to one third of its original volume? Will there be any change in the order of reaction with the reduced volume?
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