NEET2025Chemistry-Chemical Kinetics
NEET 2025 Chemistry First Order Reactions MCQ Question
Type: MCQ-numerical-Medium-Class 12
If the rate constant of a reaction is 0.03 s⁻¹, how much time does it take for 7.2 mol L⁻¹ concentration of the reactant to get reduced to 0.9 mol L⁻¹? (Given: log 2 = 0.301)
A
69.3 s
B
23.1 s
C
210 s
D
21.0 s
Correct Answer
Option A
Detailed Explanation
For a first-order reaction, t = (1/k) * ln([A]₀/[A]). Here, t = (1/0.03) * ln(7.2/0.9) = 69.3 s.
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