JEE Main 2026 — Chemical Kinetics Question with Solution
JEE Main 2026 (23 January Shift 2)
Question
Observe the following reactions at .
I. products.
II.
Both the reactions are started at 10.00 am. The rates of these reactions at 10.10 am are same. The value of at 10.10 am is . The concentration of A at 10.10 am is . What is the first order rate constant (in ) of reaction ?
I. products.
II.
Both the reactions are started at 10.00 am. The rates of these reactions at 10.10 am are same. The value of at 10.10 am is . The concentration of A at 10.10 am is . What is the first order rate constant (in ) of reaction ?
Choose an option
Show full solutionCorrect option: D
Correct answer
D
Step-by-step explanation
For reaction II:
5Br + BrO + 6H 3Br + 3HO,
The overall reaction rate is:
.
Given mol L min
The reaction rate is mol L min.
Since the rates of both reactions are equal at 10.10 am and reaction I is first-order:
, so , giving min.
5Br + BrO + 6H 3Br + 3HO,
The overall reaction rate is:
.
Given mol L min
The reaction rate is mol L min.
Since the rates of both reactions are equal at 10.10 am and reaction I is first-order:
, so , giving min.
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This is a previous-year question from JEE Main 2026, covering the Chemical Kinetics chapter of Chemistry. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.