# The rate of a first-order reaction is 0.04 mol L-1 s-1 at 10 sec and 0.03 mol L-1 s-1 at 20 sec after initiation of the reaction. The half-life period of the reaction is 1. 34.1 s 2. 44.1 s 3. 54.1 s 4. 24.7 s

Subtopic:  First Order Reaction Kinetics |
From NCERT
NEET - 2016
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NEET 2023 - Target Batch - Aryan Raj Singh
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The decomposition of phosphine (PH3) on tungsten at low pressure is a first-order reaction. It is because the

(1) rate is proportional to the surface coverage

(2) rate is inversely proportional to the surface coverage

(3) rate is independent of the surface coverage

(4) rate of decomposition is very slow

Subtopic:  First Order Reaction Kinetics |
54%
NEET - 2016
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Hints

A first order reaction has a specific reaction rate of 10-2s-1. How much time will it take for 20 g of the reactant to reduce to 5 g?

(a) 238.6 s      (b) 138.6 s        (c) 346.5  s        (d) 693.0 s

Subtopic:  First Order Reaction Kinetics |
81%
From NCERT
NEET - 2017
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Mechanism of a hypothetical reaction

is given below

(i)

(ii)

(iii)

The overall order of the reaction will be

1. 1

2.  2

3. 0

4. 1.5

Subtopic:  Order, Molecularity and Mechanism |
61%
From NCERT
NEET - 2017
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The mechanism of a hypothetical reaction

X+ Y→ 2XY  is given below:
(i) X→ X + X (Fast)
(ii) X + Y2  ⇄  XY + Y (slow)
(iii) X + Y → XY (Fast)

The overall order of the reaction will be:

1. 2

2. 0

3. 1.5

4. 1

Subtopic:  Order, Molecularity and Mechanism |
63%
NEET - 2017
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Hints

Which one of the following statements is not correct?

 1 The value of equilibrium constant is changed in the presence of a catalyst in the reaction at equilibrium 2 Enzymes catalyse mainly bio-chemical reactions 3 Coenzymes increase the catalytic activity of enzyme 4 Catalyst does not initiate any reaction
Subtopic:  Catalyst |
74%
From NCERT
NEET - 2017
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The correct difference between first- and second-order reactions is that

 1 the rate of a first-order reaction does not depend on reactant concentration; the rate of a second-order reaction does depend on reactant concentrations. 2 the half-life of a first-order reaction does not depend on [A]o; the half-life of a second-order reaction does depend on [A]0 3 a first-order reaction can be catalyzed; a second-order reaction cannot be catalyzed. 4 the rate of a first-order reaction does depend on reactant concentrations; the rate of a second-order reaction does not depend on reactant concentrations
Subtopic:  Definition, Rate Constant, Rate Law |
75%
From NCERT
NEET - 2018
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When initial concentration of the reactant is doubled, the half-life period of a zero order reaction

 1 is halved 2 is doubled 3 is tripled 4 remains unchanged
Subtopic:  Order, Molecularity and Mechanism |
74%
From NCERT
NEET - 2018
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The addition of a catalyst during a chemical reaction alters which of the following quantities?
 1 Internal energy 2 Enthalpy 3 Activation energy 4 Entropy
Subtopic:  Definition, Rate Constant, Rate Law |
93%
From NCERT
NEET - 2016
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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

Subtopic:  First Order Reaction Kinetics |
60%
From NCERT
NEET - 2016
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NEET 2023 - Target Batch - Aryan Raj Singh
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To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh