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Chemical Kinetics · Question 6

NEET (UG) 2025MCQEasy📈 Topic in 25% papers+4−1
1

If the rate constant of a reaction is 0.03 s-1, how much time does it take for 7.2 mol L-1 concentration of the reactant to get reduced to 0.9 mol L-1 ? (Given: 2 = 0.301)

  1. 210 s
  2. 21.0 s
  3. 69.3 s
  4. 23.1 s

Answer

(3) 69.3 s

Solution

The unit s-1 shows a first order reaction.

t = 2.303k [R]0[R] = 2.3030.03 7.20.9 = 2.3030.03 8

8 = 3 2 = 3 0.301 = 0.903

t = 2.303 0.9030.03 = 69.3 s

(Check: 7.2 0.9 is three half-lives; t1/2 = 0.6930.03 = 23.1 s, 3 23.1 = 69.3 s)

Answer: (3)

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2

If the half-life (t1/2) for a first order reaction is 1 minute, then the time required for 99.9\% completion of the reaction is closest to :

  1. 5 minutes
  2. 10 minutes
  3. 2 minutes
  4. 4 minutes
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3

Activation energy of any chemical reaction can be calculated if one knows the value of

  1. rate constant at standard temperature
  2. probability of collision
  3. orientation of reactant molecules during collision
  4. rate constant at two different temperatures
NEET (UG) 2024
4

Which plot of k vs 1T is consistent with Arrhenius equation?

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
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5

The rate of a reaction quadruples when temperature changes from 27 to 57 . Calculate the energy of activation. Given R = 8.314 J K-1 mol-1, 4 = 0.6021

  1. 38.04 kJ/mol
  2. 380.4 kJ/mol
  3. 3.80 kJ/mol
  4. 3804 kJ/mol
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6

Following data is for a reaction between reactants A and B : array|c|c|c| Rate ( mol L-1 s-1) & [A] & [B] \ 2 10-3 & 0.1 M & 0.1 M \ 4 10-3 & 0.2 M & 0.1 M \ 1.6 10-2 & 0.2 M & 0.2 M \ array The order of the reaction with respect to A and B, respectively, are

  1. 1, 0
  2. 0, 1
  3. 1, 2
  4. 2, 1
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7

Which of the following plot represents the variation of k versus 1T in accordance with Arrhenius equation?

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
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8

Rate constants of a reaction at 500 K and 700 K are 0.04 s-1 and 0.14 s-1, respectively; then, activation energy of the reaction is : (Given: 3.5 = 0.5441, R = 8.31 J K-1 mol-1)

  1. 182310 J
  2. 18500 J
  3. 18219 J
  4. 18030 J
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9

For a certain reaction, the rate = k[A]2[B], when the initial concentration of A is tripled keeping concentration of B constant, the initial rate would

  1. increase by a factor of six
  2. increase by a factor of nine
  3. increase by a factor of three
  4. decrease by a factor of nine
NEET (UG) 2023
10

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R. In the light of the above statements, choose the correct answer from the options given below:

  1. Both A and R are true but R is NOT the correct explanation of A.
  2. A is true but R is false.
  3. A is false but R is true.
  4. Both A and R are true and R is the correct explanation of A.
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11

The given graph is a representation of kinetics of a reaction [figure] The y and x axes for zero and first order reactions, respectively are

  1. zero order (y = concentration and x = time), first order (y = t1/2 and x = concentration)
  2. zero order (y = concentration and x = time), first order (y = rate constant and x = concentration)
  3. zero order (y = rate and x = concentration), first order (y = t1/2 and x = concentration)
  4. zero order (y = rate and x = concentration), first order (y = rate and x = t1/2)
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