NEET2017Chemistry-Chemical Kinetics
NEET 2017 Chemistry First Order Reactions MCQ Question
Type: MCQ-numerical-Medium-Class 12
A first order reaction has a specific reaction rate of 10⁻² sec⁻¹. How much time will it take for 20 g of the reactant to reduce to 5 g?
A
138.6 s
B
346.5 s
C
639.0 s
D
238.6 s
Correct Answer
Option A
Detailed Explanation
For a first order reaction, t = (1/k) * ln([R₀]/[R]). Here, k = 10⁻² sec⁻¹, [R₀] = 20 g, [R] = 5 g. t = (1/10⁻²) * ln(20/5) = 138.6 s.
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