Q. No.If the rate constant of a reaction is \(0.03 s^{-1}\) how much time does it take for \(7.2\text { mol L}^{-1}\) concentration of the reactant to get reduced to \(0.9~\text {mol L} ^{-1}\)
(Given: log 2=0.301)
1. 210 s
2. 21.0 s
3. 69.3 s
4. 23.1 s
(Given: log 2=0.301)
1. 210 s
2. 21.0 s
3. 69.3 s
4. 23.1 s
Subtopic: First Order Reaction Kinetics |
68%
From NCERT
NEET - 2025
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If the half-life \((t_{1/2})\) for a first order reaction is \(1~\text{minute}\), then the time required for \(99.9 \%\) completion of the reaction is closest to :
1. \(5~\text{minutes}\)
2. \(10~\text{minutes}\)
3. \(2~\text{minutes}\)
4. \(4~\text{minutes}\)
1. \(5~\text{minutes}\)
2. \(10~\text{minutes}\)
3. \(2~\text{minutes}\)
4. \(4~\text{minutes}\)
Subtopic: First Order Reaction Kinetics |
65%
From NCERT
NEET - 2025
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The time taken by the first order decomposition of \(\text{SO}_2\text{Cl}_2\) to decompose to 40% is 560 seconds. The rate constant for the reaction is:
(log 2.5 = 0.3979)
1. \(2.726 \times 10^{-5} \mathrm{~min}^{-1}\)
2. \(2.276 \times 10^{-5} \mathrm{~min}^{-1}\)
3. \(2.216 \times 10^{-5} \mathrm{~min}^{-1}\)
4. \(2.126 \times 10^{-5} \mathrm{~min}^{-1}\)
(log 2.5 = 0.3979)
1. \(2.726 \times 10^{-5} \mathrm{~min}^{-1}\)
2. \(2.276 \times 10^{-5} \mathrm{~min}^{-1}\)
3. \(2.216 \times 10^{-5} \mathrm{~min}^{-1}\)
4. \(2.126 \times 10^{-5} \mathrm{~min}^{-1}\)
Subtopic: First Order Reaction Kinetics |
From NCERT
NEET - 2024
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NEET 2026 - Target Batch - Vital
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For a first-order reaction A \(\rightarrow\) Products, initial concentration of A is 0.1 M, which becomes 0.001 M after 5 minutes. Rate constant for the reaction in min-1 is
| 1. | 0.2303 | 2. | 1.3818 |
| 3. | 0.9212 | 4. | 0.4606 |
Subtopic: First Order Reaction Kinetics |
71%
From NCERT
NEET - 2022
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The half-life of a first-order reaction is 2000 years. If the concentration after 8000 years is 0.02 M, then the initial concentration was:
1. 0.16 M
2. 0.32 M
3. 0.08 M
4. 0.04 M
1. 0.16 M
2. 0.32 M
3. 0.08 M
4. 0.04 M
Subtopic: First Order Reaction Kinetics |
62%
From NCERT
NEET - 2022
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The rate constant for a first order reaction is . The time required to reduce 2.0 g of the reactant to 0.2 g is:
| 1. | 200 s | 2. | 500 s |
| 3. | 1000 s | 4. | 100 s |
Subtopic: First Order Reaction Kinetics |
83%
From NCERT
NEET - 2020
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If the rate constant for a first order reaction is k, the time (t) required for the completion of 99% of the reaction is given by:
1. t = 2.303/k
2. t = 0.693/k
3. t = 6.909/k
4. t = 4.606/k
Subtopic: First Order Reaction Kinetics |
62%
From NCERT
NEET - 2019
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A first-order reaction has a rate constant of 2.303 . The time required for 40 g of this reactant to reduce to 10 g will be
[Given that ]
| 1. | 230.3 s | 2. | 301 s |
| 3. | 2000 s | 4. | 602 s |
Subtopic: First Order Reaction Kinetics |
84%
From NCERT
NEET - 2019
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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?
| 1. | 138.6 sec | 2. | 346.5 sec |
| 3. | 693.0 sec | 4. | 238.6 sec |
Subtopic: First Order Reaction Kinetics |
80%
From NCERT
NEET - 2017
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The rate of a first-order reaction is 0.04 mol l–1 s–1 at 10 seconds and 0.03 mol l–1 s–1 at 20 seconds after initiation of the reaction. The half-life period of the reaction is:
1. 44.1 s
2. 54.1 s
3. 24.1 s
4. 34.1 s
1. 44.1 s
2. 54.1 s
3. 24.1 s
4. 34.1 s
Subtopic: First Order Reaction Kinetics |
61%
From NCERT
NEET - 2016
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