For the reaction 2 N 2 O 5 ( g ) → 4 N O 2 ( g ) + O 2 ( g ) , the concentration of N O 2 increases by 2 . 4 × 10 - 2 Mol l i t - 1 in 6 seconds. The rate appearance of N O 2 and the rate of disappearance of N 2 O 5 is:

4 x 10 -3 mol L -1 sec -1 , 2 x 10 -3 mol L -1 sec -1

2 x 10 -3 mol L -1 sec -1 , 4 x 10 -3 mol L -1 sec -1

2 x 10 -3 mol L -1 sec -1 , 1 x 10 -3 mol L -1 sec -1

2 x 10 -3 mol L -1 sec -1 , 2 x 10 -3 mol L -1 sec -1

For the reaction, C 2 H 5 I + O H - → C 2 H 5 O H + I - the rate constant was found to have a value of 5 . 03 × 10 - 2 m o l - 1 d m 3 s - 1 at 289 K and 6.71 m o l - 1 d m 3 s - 1 at 333 K. The rate constant at 305 K is:

3. 3 . 15 m o l - 1 d m 3 s - 1

Chemistry - Chemical Kinetics - Quiz-6

A gaseous substance $A B_{3}$ decomposes irreversibly according to the overall equation $A B_{3} \to \frac{1}{2} A_{2} + \frac{3}{2} B_{2}$ Starting with pure $A B_{3}$ the partial pressure of the reactant varies with time for which the data are given below.
Time in hours 0 5.0 15.0 53.0

$P_{A B_{3}}$ mm Hg 660 330 165 82.5

What is the order of the reaction ?

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2
0%

0.5
0%

1
0%

1.5

The inversion of cane sugar proceeds with half life of 500 minute at pH 5 for any concentration of sugar. However if pH = 6, the half life changes to 50 minute. The rate law expression for the sugar inversion can be written as

0%

$r = K [s u g a r]^{2} [H]^{6}$
0%

$r = K [s u g a r]^{1} [H]^{0}$
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$r = K [s u g a r]^{0} [H^{+}]^{6}$
0%

$r = K [s u g a r]^{0} [H^{+}]^{1}$

The decomposition of A into product has value of k as $4.5 \times 10^{3} s^{- 1} a t 10 ° C$ and energy of activation 60 $k J m o l^{- 1}$ .

k would be $1.5 \times 10^{4} s^{- 1}$ at temperature:

0%
12 °C
0%
24 °C
0%
48 °C
0%
36 °C

Decomposition on $N H_{3}$ on heated tungsten yields the following data :

Initial pressure (mm) 65 105 y 185

Half-life (s) 290 x 670 820

What are the values of x and y in that order ?

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420 s, 110 mm
0%

500 s, 160 mm
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520 s, 170 mm
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460 s, 150 mm

The half life period of gaseous substance undergoing thermal decomposition was measured for various initial pressure ‘P’ with the following result.

P(mm) 250 300 400 450

$t_{1 / 2}$ (min) 136 112.5 85 75.5

Calculate the order of reaction.

0%

() 2
0%

() 4
0%

() 6
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() 10

For the reaction $2 N_{2} O_{5} (g) \to 4 N O_{2} (g) + O_{2} (g),$ the concentration of $N O_{2}$ increases by $2.4 \times 10^{- 2}$

Mol $l i t^{- 1}$ in 6 seconds. The rate appearance of $N O_{2}$ and the rate of disappearance of $N_{2} O_{5}$ is:

0%

2 x 10^-3 mol L^-1 sec^-1, 4 x 10^-3 mol L^-1 sec^-1
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2 x 10^-3 mol L^-1 sec^-1, 1 x 10^-3 mol L^-1 sec^-1
0%

2 x 10^-3 mol L^-1 sec^-1, 2 x 10^-3 mol L^-1 sec^-1
0%

4 x 10^-3 mol L^-1 sec^-1, 2 x 10^-3 mol L^-1 sec^-1

The rate constant of a particular reaction has the dimensions of a frequency. The order of the reaction is:

0%

Zero
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First
0%

Second
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Fractional

The reaction of iodomethane with sodium ethoxide proceeds as : $E t O^{⊝} + M e I \to E t O M e + I^{⊝}$

A plot of log $\{\frac{[M e I]}{[E t O^{⊝}]}\}$ on the Y-axis against 't' on the X-axis gives a straight line with a positive slope. What is the order of the reaction ?

0%

Second
0%

First
0%

Third
0%

Fractional

For the reaction, $C_{2} H_{5} I + O H^{-} \to C_{2} H_{5} O H + I^{-}$ the rate constant was found to have a value of $5.03 \times 10^{- 2} m o l^{- 1} d m^{3} s^{- 1}$ at 289 K and 6.71 $m o l^{- 1} d m^{3} s^{- 1}$ at 333 K.

The rate constant at 305 K is:

0%

$1.35 m o l^{- 1} d m^{3} s^{- 1}$
0%

$0.35 m o l^{- 1} d m^{3} s^{- 1}$
0%

$3. 3.15 m o l^{- 1} d m^{3} s^{- 1}$
0%

$7.14 m o l^{- 1} d m^{3} s^{- 1}$

A plot of ln rate Vs ln C for the nth order reaction gives

0%

a straight line with slope n and intercept ln $k_{n}$
0%

a straight line with slope (n – 1)
0%

a straight line with slope ln $k_{n}$ and intercept ‘n’
0%

a straight line with slope –n and intercept $k_{n}$

The first order rate constant for a certain reaction increases from $1.667 \times 10^{- 6} s^{- 1} a t 727 ° C t o 1.667 \times 10^{- 4} s^{- 1} a t 1571 ° C$ The rate constant at 1150^o C, is :
(assume activation energy is constant over the given temperature range)

0%

$3.911 \times 10^{- 5} s^{- 1}$
0%

$1.139 \times 10^{- 5} s^{- 1}$
0%

$3. 3.318 \times 10^{- 5} s^{- 1}$
0%

$1.193 \times 10^{- 5} s^{- 1}$

Assertion : Molecularity of a reaction cannot be determined experimentally.

Reason : Molecularity is assigned to the reactions on the basis of mechanism.

If both the assertion and the reason are true and the reason is a correct explanation of the assertion
If both the assertion and reason are true but the reason is not a correct explanation of the assertion
If the assertion is true but the reason is false
If both the assertion and reason are false

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1
0%
2
0%
3
0%
4

The solvolysis of 2-chloro-2-methyl propane in aqueous acetone: $H_{2} O + {(C H_{3})}_{3} C - C l \to H O - C {(C H_{3})}_{3} + H^{+} C l^{-}$ has a rate equation.

Rate = $K [(C H_{3})_{3} C - C l] .$ From this it may be inferred that the energy profile of the reaction leading from reactants to products is

(A)

(B)

(C)

(D)

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1
0%
2
0%
3
0%
4

Thermal decomposition of a compound is of first order . If 50 % of a sample of the compound is decomposed in 120 minutes , how long will it take for 90 % of the compound to decompose :

0%

410 min
0%

250 min
0%

120 min
0%

399 min

The half-life for radioactive decay of $^{14} C$ is 5730 y. An archaeological artefact contained wood had only 80% of the $^{14} C$ found in a living tree. The age of the sample is:

0%

1657.3 y
0%

1845.4 y
0%

1512.4 y
0%

1413.1 y

Two substances A and B are present such that $[A_{0}] = 4 [B_{0}]$ and half life of A is 5 minute and that of B
is 15 minute. If they start decaying at the same time following first order kinetics how much time later will the concentration of both of them would be same.

0%

15 minute
0%

10 minute
0%

5 minute
0%

12 minute

The following data were obtained during the first-order thermal decomposition of $S O_{2} C l_{2}$ at a constant volume.

$S O_{2} C l_{2} (g) \to S O_{2} (g) + C l_{2} (g)$

Experiment Time/s Total pressure/atm
1 0 0.5
2 100 0.6

The rate of the reaction when total pressure is 0.65 atm is:

0%

$7.8 \times 10^{- 4} s^{- 1} a t m .$
0%

$0.8 \times 10^{- 4} s^{- 1} a t m .$
0%

$2.4 \times 10^{- 2} s^{- 1} a t m .$
0%

$6.1 \times 10^{- 8} s^{- 1} a t m .$

Assertion : A lump of coal burns at a moderate rate in air while coal dust burns explosively.

Reason : Coal dust contains very fine particles of carbon.

If both the assertion and the reason are true and the reason is a correct explanation of the assertion
If both the assertion and reason are true but the reason is not a correct explanation of the assertion
If the assertion is true but the reason is false
If both the assertion and reason are false

0%
1
0%
2
0%
3
0%
4

Assertion : Liquid bromine reacts slowly as compared to bromine vapour.

Reason : In liquid bromine, the bromine molecules are held together by a force which is much weaker than the force existing between the two molecules of bromine in the vapour phase.

If both the assertion and the reason are true and the reason is a correct explanation of the assertion
If both the assertion and reason are true but the reason is not a correct explanation of the assertion
If the assertion is true but the reason is false
If both the assertion and reason are false

0%
1
0%
2
0%
3
0%
4

Assertion : The reaction,

$N_{2} (10 a t m) 3 H_{2} (10 a t m) \to 2 N H_{3} (g) i s f a s t e r .$

Reason : Catalyst lowers the activation energy of the reaction.

If both the assertion and the reason are true and the reason is a correct explanation of the assertion
If both the assertion and reason are true but the reason is not a correct explanation of the assertion
If the assertion is true but the reason is false
If both the assertion and reason are false

0%
1
0%
2
0%
3
0%
4

The rate of a reaction doubles when its temperature changes from 300 K to 310 K. Activation energy of such a reaction will be-

(R = 8.314 J $K^{- 1} {mol}^{- 1}$ and log 2 = 0.301)

0%

53.6 kJ $m o l^{- 1}$
0%

68.6 kJ $m o l^{- 1}$
0%

59.5 kJ $m o l^{- 1}$
0%

70.5 kJ $m o l^{- 1}$

Which is mismatched?

Assertion: All collisions of reactant molecules lead to product formation.

Reason: Only those collisions in which molecules have correct orientation and sufficient kinetic energy lead to the compound formation.

0%

Both assertion and reason are correct and the reason is the correct explanation of assertion.
0%

Both assertion and reason are correct, but reason does not explain the assertion
0%

Assertion is correct, but the reason is incorrect.
0%

The assertion is incorrect, but the reason is correct.

Assertion : For a first order reaction, the degree of dissocation is equal to $(1 - e^{- k t})$

Reason : For a first order reaction, the pre-exponential factor in the Arrhenius equation has the dimension of $t i m e^{- 1}$

If both the assertion and the reason are true and the reason is a correct explanation of the assertion
If both the assertion and reason are true but the reason is not a correct explanation of the assertion
If the assertion is true but the reason is false
If both the assertion and reason are false

0%
1
0%
2
0%
3
0%
4

At 400K energy of activation of a reaction is decreased by 0.8 kcal in presence of a catalyst. Hence rate will be-

0%

Increased by 2.71 times
0%

Increased by 1.18 times
0%

Decreased by 2.72 times
0%

Increased by 6.26 times

If $∆ H$ of a reaction is 100 kJ mol^-1, then the activation energy for forward reaction must be-

0%

Greater than 100 kJ mol^-1
0%

Less than 100 kJ mol^-1
0%

Equal to 100 kJ mol^-1
0%

None of the above.

Which one of the following statements is not correct?

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The value of equilibrium constant is changed in the presence of a catalyst in the reaction at equilibrium.
0%

Enzymes catalyse mainly bio-chemical reactions
0%

Coenzymes increase the catalytic activity of enzyme
0%

Catalyst does not initiate any reaction

The correct difference between first- and second-order reactions is that

0%

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.
0%

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
0%

a first-order reaction can be catalyzed; a second-order reaction cannot be catalyzed.
0%

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

When initial concentration of the reactant is doubled, the half-life period of a zero order reaction

0%

is halved
0%
is doubled
0%
is tripled
0%
remains unchanged

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Practice Chemistry Quiz Questions and Answers

0:0:1

Practice Chemistry Quiz Questions and Answers

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