Chemical Kinetics Practice Questions
JEE · Chemistry · 1277 free MCQs with instant results and detailed explanations.
1277
Total
263
Easy
579
Medium
435
Hard
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Topics in Chemical Kinetics
Rate of Reaction
187
Rate Law
181
Order of Reaction
201
Integrated Rate Equations
192
Half-Life
149
Arrhenius Equation
193
Collision Theory
174
Sample Questions from Chemical Kinetics
Here are 10 sample questions. Start a quiz to get randomized questions with scoring.
Q1
Easy
What is the unit of the rate constant for a first-order reaction?
A.
s⁻¹
B.
M⁻¹s⁻¹
C.
M⁻²s⁻¹
D.
M²s⁻¹
Show Answer & Explanation
Correct Answer: A
For a first-order reaction, the rate constant has units of s⁻¹, indicating the rate of change of concentration over time.
Q2
Easy
In a chemical reaction, if the concentration of reactants is doubled, how does the rate change in a second-order reaction?
A.
Remains the same
B.
Doubles
C.
Quadruples
D.
Halves
Show Answer & Explanation
Correct Answer: C
In a second-order reaction, the rate is proportional to the square of the concentration. Doubling the concentration results in a fourfold increase in the rate.
Q3
Easy
Which of the following factors does NOT affect the rate of a chemical reaction?
A.
Temperature
B.
Concentration of reactants
C.
Presence of a catalyst
D.
Color of reactants
Show Answer & Explanation
Correct Answer: D
The color of reactants does not influence the rate of reaction, while temperature, concentration, and catalysts do.
Q4
Medium
For a first-order reaction, if the half-life is 10 minutes, what will be the time required for 75% of the reactant to be converted into products?
A.
30 minutes
B.
20 minutes
C.
15 minutes
D.
25 minutes
Show Answer & Explanation
Correct Answer: A
For a first-order reaction, the half-life is constant. The time taken to reach 75% completion is equal to three half-lives (10 + 10 + 10 = 30 minutes).
Q5
Medium
Which of the following factors does NOT affect the rate of a chemical reaction?
A.
Concentration of reactants
B.
Temperature
C.
Nature of the reactants
D.
The color of reactants
Show Answer & Explanation
Correct Answer: D
The color of reactants does not influence the rate of a reaction, whereas concentration, temperature, and nature of reactants do.
Q6
Medium
What is the effect of increasing the temperature on the rate constant (k) of an endothermic reaction?
A.
Increases k
B.
Decreases k
C.
No effect on k
D.
First increases, then decreases
Show Answer & Explanation
Correct Answer: A
Increasing temperature usually increases k for endothermic reactions as it provides energy to overcome the activation barrier.
Q7
Medium
The rate of a reaction is proportional to the concentration of a reactant raised to the power of 2. What is the order of the reaction?
A.
0
B.
1
C.
2
D.
3
Show Answer & Explanation
Correct Answer: C
The order of the reaction is the sum of the powers of the concentration terms in the rate equation; hence it is second order.
Q8
Hard
A reaction follows first-order kinetics. If the half-life of the reaction is 10 minutes, what will be the time taken for the concentration of the reactant to reduce to one-eighth of its initial value?
A.
30 minutes
B.
20 minutes
C.
40 minutes
D.
50 minutes
Show Answer & Explanation
Correct Answer: A
In first-order reactions, the time taken to reduce the concentration to one-eighth is three half-lives. Therefore, it will take 3 × 10 minutes = 30 minutes.
Q9
Hard
The activation energy (Ea) of a reaction is 100 kJ/mol. If the temperature increases from 298 K to 318 K, what is the approximate increase in the rate constant (k) using the Arrhenius equation (R=8.314 J/mol·K)?
A.
Approx. 2 times
B.
Approx. 4 times
C.
Approx. 10 times
D.
Approx. 20 times
Show Answer & Explanation
Correct Answer: B
Using the Arrhenius equation and calculating k at both temperatures indicates an increase in k by roughly a factor of 4.
Q10
Hard
A reaction has a rate constant of 0.5 s^-1 at 300 K. What will be the rate constant at 400 K if the activation energy for the reaction is 75 kJ/mol? (Use R = 8.314 J/mol·K)
A.
1.5 s^-1
B.
2.0 s^-1
C.
3.0 s^-1
D.
4.0 s^-1
Show Answer & Explanation
Correct Answer: C
Using the Arrhenius equation, k can be calculated for the new temperature, revealing a value of approximately 3.0 s^-1.
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Chemical Kinetics — JEE Chemistry Practice Questions Online
This page contains 1277 practice MCQs for the chapter Chemical Kinetics in JEE Chemistry. The questions are organized by difficulty — 263 easy, 579 medium, 435 hard — so you can choose the right level for your preparation.
Every question includes a detailed explanation to help you understand the concept, not just memorize answers. Take a timed quiz to simulate exam conditions, or practice at your own pace with no time limit. This chapter covers 7 topics, giving you comprehensive coverage of the entire chapter.