The time for the half-life of a first-order reaction is 1 hr. The time taken for 87.5% completion of the reaction is-

1. 1 hour

2. 2 hour

3. 3 hour

4. 4 hour

Subtopic:  First Order Reaction Kinetics |
 79%
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Which order of reaction obeys the relation t1/2 = 1/Ka?

(a) First

(b) Second

(c) Third

(d) Zero

Subtopic:  Order, Molecularity and Mechanism |
 79%
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The chemical reaction, 2O3 3O2 proceeds as follows;

O3 O2 + O .....(Fast)

O+O3  2O2 ....(Slow)

The rate law expression should be:

(a) r = K[O3]2

(b) r = K[O3]2[O2]-1

(c) r = K[O3][O2]

(d) unpredictable

Subtopic:  Definition, Rate Constant, Rate Law |
 71%
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The rate of reaction becomes 2 times for every 10°C rise in temperature. How the rate of reaction will increase when temperature is increased from 30°C to 80°C?

(a) 16

(b) 32

(c) 64

(d) 128

Subtopic:  Definition, Rate Constant, Rate Law |
 87%
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The fraction of a reactant showing first-order reaction remains after 40 minutes if t1/2 is 20 minutes -

1. 1/4

2. 1/2

c. 1/8

4. 1/6

Subtopic:  First Order Reaction Kinetics |
 77%
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For the reaction 2NO2 + F2 → 2NO2F, following

mechanism has been provided,

 NO2 + F2   slow  NO2F+F

NO2 + F   fast NO2F

Thus, rate expression of the above

reaction can be written as:

(a) r = K[NO2]2[F2]

(b) r = K[NO2 ][F2]

(c) r = K[NO2]

(d) r = K[F2]

Subtopic:  Definition, Rate Constant, Rate Law |
 89%
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For the reaction:

[Cu(NH3)4]2+ + H2O[Cu(NH3)3H2O]2+ + NH3

the net rate of reaction at any time is given by, net rate =

2.0x10-4 [Cu(NH3)4]2+[H2O] - 3.0x105 [Cu(NH3 )3 H20]2+[NH3]

Then correct statement is/are :

(a) rate constant for forward reaction = 2 x 10-4

(b) rate constant for backward reaction = 3 x 105

(c) equilibrium constant for the reaction = 6.6 x 10-10

(d) all of the above

Subtopic:  Definition, Rate Constant, Rate Law |
 85%
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Subtopic:  Definition, Rate Constant, Rate Law |
 96%
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A reactant with initial concentration 1.386 mol litre-1 showing first order change takes 40 minute to become half. If it shows zero order change taking 20 minute to becomes half under the similar conditions, the ratio, K1/K0 for first order and zero order kinetics will be:

(1) 0.5 mol-1 litre

(2) 1.0 mol/litre

(3) 1.5 mol/litre

(4) 2.0 mol-1 litre

 

Subtopic:  First Order Reaction Kinetics |
 75%
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In a first order reaction, the concentration of the reactant is decreased from 1.0 M to 0.25M in 20 minute. The rate constant of the reaction would be:

(1) 10min-1

(2) 6.931 min-1

(3) 0.6931 min-1

(4) 0.06931 min-1

Subtopic:  First Order Reaction Kinetics |
 76%
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