Half-life is independent of the concentration of a reactant. After 10 minutes, the volume of N2 gas is 10 L and after complete reaction, it is 50 L. Hence, the rate constant is:

1. 2.30310log 5 min-1

2. 2.30310 log 1.25 min-1

3. 2.30310 log 2 min-1

4. 2.30310 log 4 min-1

Subtopic:  First Order Reaction Kinetics |
Level 3: 35%-60%
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The activation energies of the forward and backward reactions in the case of a chemical reaction are 30.5 and 45.4 KJ/mol respectively. The reaction is

1. Exothermic

2. Endothermic

3. Neither exothermic nor endothermic

4. Independent of temperature

Subtopic:  Arrhenius Equation |
 79%
Level 2: 60%+
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The first order reaction \(\text{PCl}_5 (g) \rightarrow \text{PCl}_3 (g) + \text{Cl}_2 (g)\)  has a half-life (\(t_{0.5}\)​) of 20 minutes. What is the time required for the concentration of \(\text{PCl}_5\) to decrease to 25% of its initial concentration?

1. 22 min 2. 40 min
3. 90 min 4. 50 min
Subtopic:  First Order Reaction Kinetics |
 82%
Level 1: 80%+
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In the reaction A + B → C, if the concentration of A reduces from 4M to 2M in 1 hour, followed by a reduction from 2M to 1M in 0.5 hours, the order of the reaction is:

1. One

2. Zero

3. Two

4. Three

Subtopic:  Definition, Rate Constant, Rate Law |
 61%
Level 2: 60%+
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A gaseous reaction A2(g) → B(g) + 12C(g) shows increase in pressure from 100 mm to 120 mm in 5 minutes. The rate of disappearance of Awill be : 

1. 4 mm min-1 2. 8 mm min-1
3. 16 mm min-1 4. 2 mm min-1
Subtopic:  Definition, Rate Constant, Rate Law |
Level 3: 35%-60%
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During the formation of ammonia by Haber's process N+ 3H2 → 2NH3, the rate of appearance of NH3 was measured as 2.5 x 10-4 mol L-1 s-1. The rate of disappearance of H2 will be: 

1. 2.5 x 10-4 mol L-1 s-1

2. 1.25 x 10-4 mol L-1 s-1

3. 3.75 x 10-4 mol L-1 s-1

4. 15.00 x 10-4 mol L-1 s-1

Subtopic:  Definition, Rate Constant, Rate Law |
 85%
Level 1: 80%+
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For a chemical reaction, A   products, the rate of reaction doubles when the concentration of A is increased by 4 times. The order of the reaction is 

1. 4

2. 0

3. 1/2

4. 1

 

Subtopic:  Order, Molecularity and Mechanism |
 84%
Level 1: 80%+
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The correct expression for the 3/4th life of a first-order reaction is:
\(1 .  \frac{k}{2 . 303} log \frac{4}{3}\)
\(2 .  \frac{2 . 303}{k} log \frac{3}{4}\)
\(3 .  \frac{2 . 303}{k} log\) \(4\)
\(4 .  \frac{2 . 303}{k}\) \(log\) \(3\)

Subtopic:  Definition, Rate Constant, Rate Law |
 63%
Level 2: 60%+
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From the plot of log k vs 1/T, following parameter can be calculated:

1. Activation energy.

2. Rate constant of reaction .

3. Order of reaction.

4. Activation energy as well as the frequency factor.

Subtopic:  First Order Reaction Kinetics |
 53%
Level 3: 35%-60%
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Find the minimum possible value of activation energy, Eₐ, for an endothermic reaction having enthalpy change ΔH.

1. Less than ΔH

2. Zero

3. More than ΔH

4. Equal to ΔΗ

Subtopic:  Arrhenius Equation |
 71%
Level 2: 60%+
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