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 |
 69%
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
Subtopic:  First Order Reaction Kinetics |
 61%
From NCERT
NEET - 2022
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The rate constant for a first order reaction is 4.606×10-3 s-1. 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 |
 81%
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 |
 59%
From NCERT
NEET - 2019
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A first-order reaction has a rate constant of 2.303×10-3 s-1. The time required for 40 g of this reactant to reduce to 10 g will be [Given that log102=0.3010]

1. 230.3 s

2. 301 s

3. 2000 s

4. 602 s

Subtopic:  First Order Reaction Kinetics |
 83%
From NCERT
NEET - 2019
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