WBJEE SERIES Chemistry
Chemical Kinetics
17 previous year questions.
Volume: 17 Ques
Yield: Medium
High-Yield Trend
1
2025 2
2024 3
2023 1
2019 1
2016 1
2015 1
2014 1
2013 1
2012 1
2010 2
2009 1
2007 1
2001 Chapter Questions 17 MCQs
01
PYQ 2001
hard
chemistry ID: wbjee-20
A human body required the 0.01 M activity of radioactive substance after 24 h. Half-life of radioactive substance is 6 h. Then, injection of maximum activity of radioactive substance that can be injected will be
1
0.08
2
0.04
3
0.16
4
0.32
02
PYQ 2007
medium
chemistry ID: wbjee-20
The half-life period of radioactive element is days. After days, gram of element will reduce to
1
2
3
4
03
PYQ 2009
hard
chemistry ID: wbjee-20
The half-life of a radioactive element is 10 hours. How much will be left after 4 hours in 1 g atom sample?
1
atoms
2
atoms
3
atoms
4
atoms
04
PYQ 2009
easy
chemistry ID: wbjee-20
The time taken for completion of a first order reaction is minutes. Then for completion the reaction will take
1
2
3
4
05
PYQ 2010
medium
chemistry ID: wbjee-20
For a reversible chemical reaction where the forward process is exothermic, which of the following statements is correct ?
1
The backward reaction has higher activation energy than the forward reaction
2
The backward and the forward processes have the same activation energy
3
The backward reaction has lower activation energy
4
No activation anergy is required at all since energy is liberated in the process.
06
PYQ 2012
medium
chemistry ID: wbjee-20
Which one of the following is wrong about molecularity of a reaction?
1
It may be whole number or fractional
2
It is calculated from reaction mechanism
3
It is the number of molecules of the reactants taking part in a single step chemical reaction
4
It is always equal to the order of elementary reaction.
07
PYQ 2013
medium
chemistry ID: wbjee-20
Acid catalysed hydrolysis of ethyl acetate follows a pseudo-first order kinetics with respect to ester. If the reaction is carried out with large excess of ester, the order with respect to ester will be
1
1.5
2
0
3
2
4
1
08
PYQ 2014
medium
chemistry ID: wbjee-20
A piece of wood from an' archaeological sample has counts per gram of , while a fresh sample of wood has a count of . If half-life of is , the age of the archaeological sample is
1
8,500 years
2
9,200 years
3
10,000 years
4
11,000 years
09
PYQ 2015
medium
chemistry ID: wbjee-20
For the reaction , the reaction rate is doubled, if the concentration of is doubled. The rate is increased by four times when concentrations of both and are increased by four times. The order of the reaction is
1
3
2
0
3
1
4
2
10
PYQ 2016
medium
chemistry ID: wbjee-20
75% of a first order reaction was completed in 32 min. When would 50% of the reaction completed?
1
24 min
2
16 min
3
8 min
4
64 min
11
PYQ 2019
medium
chemistry ID: wbjee-20
The kinetic study of a reaction like vA P at 300 K provides the following curve, where concentration is taken in mol dm and time in min. Identify the correct order(n) and rate constant(k) :
1
n = 0, k = 4.0 mol dm
2
n = 1/2, k = 2.0
3
n = 1, k = 8.0
4
n = 2, k = 16.0
12
PYQ 2023
medium
chemistry ID: wbjee-20
If in the case of a radio-isotope, the value of half-life(T1/2) and decay constant(λ) are identical in magnitude, then their value should be
1
2
(0.693)1/2
3
(0.693)2
4
0.693
13
PYQ 2023
medium
chemistry ID: wbjee-20
Which of the following would give a linear plot? (K is the rate constant of an elementary reaction and T is the temperature in absolute scale)
1
k vs T
2
k vs
3
ln k vs T
4
ln k vs
14
PYQ 2023
medium
chemistry ID: wbjee-20
For the reaction A+B C, we have the following data:
The order of the reaction with respect to A and B are:
| Initial concentration of A(in molarity) | Initial concentration of B (in molarity) | Rate(initial)(Relevant unit) |
| 1 | 10 | 100 |
| 1 | 1 | 1 |
| 10 | 1 | 10 |
The order of the reaction with respect to A and B are:
1
Not possible to tell with the given data
2
First order with respect to both A and B
3
First order with respect to A and second order with respect to B.
4
Second order with respect to A and first order with respect to B.
15
PYQ 2024
medium
chemistry ID: wbjee-20
Which of the following statements is true about the equilibrium constant and rate constant of a single-step chemical reaction?
1
Equilibrium constant may increase or decrease, but rate constant always increases with temperature.
2
Both equilibrium constant and rate constant increase with temperature
3
Rate constant may increase or decrease, but equilibrium constant always increases with temperature.
4
Both equilibrium constant and rate constant decrease with temperature
16
PYQ 2024
medium
chemistry ID: wbjee-20
For a first-order reaction with rate constant k, the slope of the plot of log(reactant concentration) against time is:
1
k/2.303
2
k
3
−k/2.303
4
-k
17
PYQ 2025
medium
chemistry ID: wbjee-20
For a chemical reaction, half-life period is 10 minutes. How much reactant will be left after 20 minutes if one starts with 100 moles of reactant and the order of the reaction is:
1
zero, (ii) one, and (iii) two?
2
0, 25, 33.33
3
25, 0, 33.33
4
33.33, 25, 0
About Chemical Kinetics - WBJEE
Chemical Kinetics is a vital chapter for WBJEE aspirants. Mastering the concepts covered in this chapter is essential for securing a top rank.
By rigorously practicing the previous year questions associated with this chapter, you can identify high-yield topics, understand the examiner's perspective, and boost your confidence during the actual exam.
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Analyzing PYQs for this specific chapter reveals the most frequently tested concepts and the typical complexity of questions, allowing you to tailor your study plan efficiently.
How to best use this analysis?
Review the topic breakdown to see which sub-topics within Chemical Kinetics carry the most weight. Then, tackle the questions iteratively to solidify your understanding.