For a chemical reaction: \(A\rightarrow D\)

Mechanism is expressed in three steps:
Step -1 : \(\mathrm{A} \rightarrow \mathrm{~B}: \Delta \mathrm{H}=+\mathrm{ve}\)
Step -2 : \( B \rightarrow C: \Delta H=-\mathrm{ve} \)
Step -3 : \( C \rightarrow D: \Delta H=-\mathrm{ve}\)
1.   2.  
3.   4. 
Subtopic:  First Order Reaction Kinetics | Order, Molecularity and Mechanism |
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Consider the following reaction sequence involving first order reactions:
\(\mathrm{A} \xrightarrow{\mathrm{k}_1} \mathrm{~B} \xrightarrow{\mathrm{k}_2} \mathrm{C}\)

If net rate of formation of B is zero, what would be concentration of B in terms of concentration of A?
1. \(\mathrm{k}_1 \mathrm{k}_2[\mathrm{~A}] \)
2. \( \frac{k_1}{k_2}[A]\)
3. \( \left(k_1+k_2\right)[A] \)
4. \( \frac{k_2}{k_1}[A]\)
Subtopic:  Order, Molecularity and Mechanism |
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Consider the given reaction:
\(\mathrm{N}_2 \mathrm{O}_4 \rightarrow 2 \mathrm{NO}_2\) 
Initial conc. of \(\text{N}_2\text{O}_4=3\text{M}\)
If the concentration of \(\text{N}_2\text{O}_4\) is 2.75 M, after 30 sec., then find out the rate of formation of \(\text{NO}_2\) during this interval in \(\text {mol} ~ \text{lit}^{-1}~\text{min}^{-1}\)

1. 4 
2. 1
3. 6 
4. 0
Subtopic:  Order, Molecularity and Mechanism |
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The rate law for a reaction is rate = k[A]²[B]. If the concentrations of both A and B are doubled, the rate becomes x times the original rate, and the overall order of the reaction is y. The value of (x + y) is:

1. 11 2. 87
3. 67 4. 20
Subtopic:  Order, Molecularity and Mechanism |
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The results given in the below table were obtained during kinetic studies of the following reaction:
2A + B C + D

 Experiment  [A]/mol L-1  [B]/mol L-1  Initial rate/mol L-1 min-1
           I       0.1        0.1  6.00×10-3
          II        0.1        0.2  2.40×10-2
          III        0.2        0.1  1.20×10-2
           IV         X        0.2  7.20×10-2
           V        0.3          Y  2.88×10-1

X and Y in the given table are respectively :

1. 0.3, 0.4

2. 0.4, 0.3

3. 0.4, 0.4

4. 0.3, 0.3

Subtopic:  Order, Molecularity and Mechanism |
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For the reaction \(2 A+B \rightarrow C,\) the values of initial rate at different reactant concentrations are given in the table below. The rate law for the reaction is:

[A] (mol L-1) [B] (mol L-1) Initial Rate (mol L-1 s-1)
0.05 0.05 0.045
0.10 0.05 0.090
0.20 0.10 0.72
 
1. \(\text { Rate }=\mathrm{k}[A][B]\) 2. \(\text { Rate }=\mathrm{k}[\mathrm{~A}][B]^2\)
3. \(\text { Rate }=\mathrm{k}[A]^2[B]^2\) 4. \(\text { Rate }=\mathrm{k}[A]^2[B]\)
Subtopic:  Order, Molecularity and Mechanism |
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For the non – stoichiometry reaction 2A + B → C + D, the following kinetic data were obtained in three separate experiments (all at 298 K).

Initial Concentration (A) Initial Concentration (B) Initial rate of formation of C (mol L S)
0.1 M
0.1 M
0.2 M
0.1 M
0.2 M
0.1 M
1.2 × 10–3
1.2 × 10–3
2.4 × 10–3

The rate law for the formation of C is:

1. dcdt=k[A]2[B]

2. dcdt=k[A][B]2

3. dcdt=k[A]

4. dcdt=k[A][B]

Subtopic:  Order, Molecularity and Mechanism |
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Find out the order of a reaction \(A + 2B\rightarrow C\) , if the rate is given by \(+\frac{d[C]}{d t}=k[A][B]\)

1. Three (3)

2. Two (2)

3. One (1)

4. Zero (0)

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H2 gas is absorbed on the metal surface like gold, tungsten, etc. This follows ________ order reaction:

1. Third 2. Second
3. Zero 4. First
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For the reaction system : \(2 \mathrm{NO}(g)+\mathrm{O}_{2}(g) \longrightarrow 2 \mathrm{NO}_{2}(g)\), volume is suddenly reduced to half its value by increasing the pressure. If the reaction is of first order with respect to O2 and second order with respect to NO; the rate of reaction will:

1. Diminish to one -fourth of its initial value 

2. Diminish to one-eighth of its initial value 

3. Increase to eight times of its initial value 

4. Increase to four times of its initial value 

Subtopic:  Order, Molecularity and Mechanism |
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