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Chemistry · Chemical Kinetics

NEET (UG) 2025 — Question 52

If the half-life ( t1/2\mathrm{t}_{1 / 2} ) for a first order reaction is 1 minutes, then the time required for 99.9%99.9\% completion of the reaction is closest to:

  1. Option A:

    2 minutes

  2. Option B:

    4 minutes

  3. Option C:

    5 minutes

  4. Option D:

    10 minutes

    Correct

Answer: D

Step-by-step solution

For 1st 1^{\text {st }} order reactions: t99.9%=10×t1/2\quad t_{99.9 \%}=10 \times t_{1 / 2}

t99.9%=10×1=10 minute \begin{aligned} \mathrm{t}_{99.9 \%} & =10 \times 1 \\& =10 \text { minute } \end{aligned}

Answer key and solution verified before publishing.

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Exam
NEET (UG) 2025
Paper
2025 paper
Subject
Chemistry
Chapter
Chemical Kinetics
Topic
Integrated Rate Laws

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