# The rate constant for a reaction of zero-order in A is 0.0030 mol L-1 s-1. How long will it take for the initial concentration of A to fall from 0.10 M to 0.075 M? 1. 8.3 sec 2. 0.83 sec 3. 83 sec 4. 10.3 sec

Subtopic:  Definition, Rate Constant, Rate Law |
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The reaction of hydrogen and iodine monochloride is given as:
H2(g) + 2ICl(g) → 2HCl(g) + I2(g
This reaction is of first order with respect to H2(g) and ICl(g), for which of the following proposed mechanisms:
Mechanism A:
H2(g) + 2ICl(g) → 2HCl(g) + I2(g
Mechanism B:
H2(g) + ICl(g) →HCl(g) + HI(g); slow
HI(g) + ICl(g) →HCl(g) + I2(g); fast

1. B Only

2. A and B both

3. Neither A nor B

4. A only

Subtopic:  First Order Reaction Kinetics |
63%
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AIPMT - 2007
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If 'a' is the initial concentration of a substance that reacts according to zero-order kinetics and k is the rate constant, then the time for the reaction to go to completion is:
1. a/k
2. 2/ka
3. k/a
4. 2k/a

Subtopic:  First Order Reaction Kinetics |
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Consider the first-order gas-phase decomposition reaction given below.

A(g) → B(g) + C(g)

The initial pressure of the system before the decomposition of A was ${\mathrm{P}}_{\mathrm{i}}$. After the lapse of time t, the total pressure of the system increased by X units and became ${\mathrm{P}}_{\mathrm{t}}$. The rate constant k for the reaction is:

1. $\mathrm{k}=\frac{2.303}{\mathrm{t}}\mathrm{log}\frac{{P}_{\mathrm{i}}}{{P}_{\mathrm{i}}-\mathrm{x}}$

2. $\mathrm{k}=\frac{2.303}{\mathrm{t}}\mathrm{log}\frac{{P}_{\mathrm{i}}}{2{P}_{\mathrm{i}}-{P}_{\mathrm{t}}}$

3. $\mathrm{k}=\frac{2.303}{\mathrm{t}}\mathrm{log}\frac{{P}_{\mathrm{i}}}{2{P}_{\mathrm{i}}+{P}_{\mathrm{t}}}$

4. $\mathrm{k}=\frac{2.303}{\mathrm{t}}\mathrm{log}\frac{{P}_{\mathrm{i}}}{{P}_{\mathrm{i}}+\mathrm{x}}$

Subtopic:  First Order Reaction Kinetics |
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The correct graphical representation of first-order reaction is:

 (a) (b) (c) (d)

 1 (a) and (b) 2 (b) and (c) 3 (c) and (d) 4 (a) and (d)
Subtopic:  First Order Reaction Kinetics |
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Match the statements in Column I and Column II :
 Column I Column II A. Catalyst alters the rate of reaction 1. Proper orientation is not there always B. ${\mathrm{e}}^{-{\mathrm{E}}_{\mathrm{a}}/\mathrm{RT}}$ 2. By lowering the activation energy C. Energetically favorable reactions are sometimes slow 3. Total probability is one D. Area under the Maxwell-Boltzmann curve is constant 4. Refers to the fraction of molecules with energy equal to or greater than the activation energy

Codes

 A B C D 1. 2 4 1 3 2. 3 1 4 2 3. 1 4 3 2 4. 3 4 1 2
Subtopic:  Catalyst |
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Select the correct option based on statements below:

 Assertion (A): The enthalpy of reaction remains constant in the presence of a catalyst. Reason (R): A catalyst participating in the reaction forms a different activated complex and lowers down the activation energy but the difference in energy of the reactant and the product remains the same.

 1 Both (A) and (R) are true and (R) is the correct explanation of (A). 2 Both (A) and (R) are true but (R) is not the correct explanation of (A). 3 (A) is true but (R) is false. 4 Both (A) and (R) are false.
Subtopic:  Catalyst |
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For a first-order reaction A → B the reaction rate at a reactant concentration of 0.01M is found to be . The half-life period of the reaction is:

 1 300s 2 30s 3 220s 4 347s
Subtopic:  First Order Reaction Kinetics |
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AIPMT - 2005
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The decomposition of N2O5 in CCl4 at 318K has been studied by monitoring the concentration of N2O5 in the solution. Initially, the concentration of N2O5 is 2.33 mol L–1 and after 184 minutes, it is reduced to 2.08 mol L–1. The reaction takes place according to the equation

2 N2O5 (g)  4 NO2 (g) + O2 (g)

The rate of production of NO2 during this period is-

1. 5.72 × 10
–3 mol L–1 min–1
2. 2.72 × 10
–3 mol L–1 min–1
3. 1.72 × 10
–5 mol L–1 min–1
4. 6.72 × 10
–4 mol L–1 min–1

Subtopic:  Definition, Rate Constant, Rate Law |
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In a first order reaction, time required for completion of 99.9% is X times of half-life (t1/2) of the reaction. When reaction is completed 99.9%, [R]n = [R]0 – 0.999[R]0 .The value of X is-

1. 5
2. 10
3. 15
4. 20

Subtopic:  First Order Reaction Kinetics |
80%
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