PYQSide ExamsMy practice

Chemical Kinetics · Question 5

RE-NEET (UG) 2026MCQMedium📈 Topic in 25% papers+4−1
1

2A k B is a zero-order reaction, where k = 1.0 mol L-1 min-1. If the initial concentration of A is 2 M, then the time taken to complete 75\% of the reaction will be

  1. 2.0 min
  2. 1.5 min
  3. 0.75 min
  4. 1.0 min

Answer

(3) 0.75 min

Solution

For the reaction 2A k B:

Rate = - 12 d[A]dt = k - d[A]dt = 2k

Integrating for zero-order kinetics:

[A]0 - [A]t = 2kt

For 75\% completion, the amount of A reacted is:

[A]0 - [A]t = 0.75 [A]0 = 0.75 2 M = 1.5 M

1.5 = 2 1.0 t

t = 1.52.0 = 0.75 min

Answer: (3)

RE-NEET (UG) 2026

Keep practising — Chemical Kinetics

2

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
NEET (UG) 2025
3

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
NEET (UG) 2025
4

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
5

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

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
NEET (UG) 2024
6

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
NEET (UG) 2024
7

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
RE-NEET (UG) 2024
8

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]
RE-NEET (UG) 2024
9

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
RE-NEET (UG) 2024
10

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
11

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.
NEET (UG) 2023

All Chemical Kinetics PYQs →

PDFDownload Chemical Kinetics PYQs as PDF Free, with answer key and a QR code to every solution — print it or study offline⬇
All NEET Chemistry chapters