Chemical Kinetics Class 12 Chemistry Free Online Mock Test 1

5/5 - (2 votes)

🧪Chemical Kinetics – 25 MCQ Quiz
🔢 Number of Questions: 25 MCQs
⏱️ Time Required: 20 minutes
📚 Subject: Chemistry (Chemical Kinetics)
🎯 Difficulty Level: Moderate (10+2 / NEET Level)
👨‍🎓 Ideal For:
NEET UG aspirants
10+2 Board/NCERT/17+Age Chemistry students
Competitive exam learners
📌 Key Features:
Concept-based questions
Covers important periodic trends
Helps in quick revision
Useful for mock test practice
🚀 Outcome:
After completing this quiz, you will be able to confidently understand and apply Chemical Kinetics in exams.

1 / 25
1
2
3
4

2 / 25
1
2
3
4

3 / 25
1
2
5/3
0

4 / 25
In 30 minutes, a first-order reaction is 50% complete. Calculate the amount of time it took to complete 87.5 percent of the reaction.
a) 30 minutes
b) 60 minutes
c) 90 minutes
d) 120 minutes

Explanation: In 30 minutes, the reaction is 50% complete. As a result, t1/2 = 30 minutes.
In two half-lives, 75% of the process is accomplished. As a result, t = 2 ×30 = 60 minutes.
In three half-lives, 87.5 percent of the reaction is finished.
Hence, t = 3 × 30 = 90 minutes.

5 / 25
In a reaction, what is the driving force?
a) Energy given
b) Energy released
c) Free energy
d) None of the mentioned

6 / 25
2
1
1.5
Zero

7 / 25
If a reaction’s rate is represented as rate = k [A]² [B], the reaction’s order will be
1
2
3
4

8 / 25
A reaction’s rate constant is k=3.28 × 10^-4 s^-1. Determine the reaction’s order.
a) First order
b) Second order
c) Third order
d) Fourth order

Answer-:: a)first order
Explanation: Given that k= 3.28 × 10^-4s^-1
The standard formula for calculating rate constant units is k=(mol L^-1)^1-ns^-1, where n is the order of the reaction. For (mol L^-1)^1-ns-1 to become s-1, the value of n must be 1. As a result, k=3.28 × 10^-4s^-1 denotes a first order reaction.

9 / 25
Dimethyl ether breakdown is a fractional order process. rate =k(PCH₃OCH₃)^3/2 gives the rate. What are the units of rate and rate constant if pressure is measured in bars and time is measured in minutes?
(a bar min-1, bar2 min^-1
(b) bar min^-1, bar^1/2 min^-1
(c) bar^1/2 min^-1, bar² min^-1
(d) bar min^-1, bar^1/2 min^-1
a
b
c
d

10 / 25
The reaction NO₂ + CO → NO + CO₂ occurs in two steps. Locate the rate law.
2NO₂ → NO + NO₃ (k1) – slow
NO₃ + CO → CO₂ + NO₂ (k2) – fast
a) R = k1 [NO₂] ³
b) R = k2 [NO₃] [CO]
c) R = k1 [NO₂]
d) R = k1 [NO₂]²
a
b
c
d

Answer: d) R = k1 [NO₂]²
Explanation: In any reaction, the slowest step is the rate determining step; the overall reaction rate is determined by this step. As a result, the rate determining step is 2NO₂= NO + NO₃(k1). As a result, the rate rule R= k1[NO₂]² .

11 / 25
Which of the following reactions is an example of a fractional order reaction?
((a) NH₄NO₂ → N₂+ 2H2O
(b) NO + O₃→ NO₂+ O₂
(c) 2NO + Br₂→ 2NOBr
(d) CH₃CHO → CH₄+ CO
a
b
c
d

12 / 25
The rate constant for the reaction 2H₂ + 2NO → 2H₂O + N₂ with rate = K|H₂||NO|², is
(a) mol L^-1 s^-1
(b) s^-1
(c) mol^-2 L² s^-1
(d)mol L^-1
a
b
c
d

13 / 25
What is the rate law for acid hydrolysis of an ester in aqueous solution, such as CH₃COOC₂H₅?
a) k [CH₃COOC₂H₅]
b) k [CH₃COOC₂H₅] [H₂O]
c) k [CH₃COOC₂H₅]²
d) k
a
b
c
d

Explaination-: : Acid hydrolysis of ester, CH₃COOC₂H₅ + H₂O → CH₃COOH + C₂H₅OH
When one reactant is taken in excess of the other, the reaction’s sequence can be changed.
Water is present in excess according to the rate law R= k [CH₃COOC₂H₅] [H₂O].
As a result, R=k [CH₃COOC₂H₅].

14 / 25
If the concentration of material X is doubled and that of Y is halved, how many times will the rate of the elementary reaction 3X + Y = X₂Y change?
a) r2= 4.5r1
b) r2= 5r1
c) r2= 2r1
d) r2= 4r1
a
b
c
d

Answer: d) r2= 4r1
Because it is an elementary reaction, the rate law r1= k [A]³[B]
The new rate will be r2=k when the concentrations are changed
r2= k (2[A])3([B]/2) = 4k[A]³[B]
As a result, r2=4r1

15 / 25
A reaction’s rate constant is determined by
(a) temperature of the reaction
(b) extent of the reaction
(c) initial concentration of the reactants
(d) the time of completion of reaction

Answer: (d) the time of completion of reaction
Explanation-: The rate of reaction constant is determined by the time taken by the reaction is completed by time taken to completion of the whole reaction.

16 / 25
The chemical reaction, 2O₃→ 3O₂ Proceeds as
O₃ ⇌ O₂+ |O| (fast)
|O| + O₃ → 2O₂ (slow)
The rate law expression will be
(a) Rate = k [O] [O₃]
(b) Rate = k [O₃]² [O2]^-1
(c) Rate = k [O₃]²
(d) Rate = k [O₂] [O]
a
b
c
d

17 / 25
For a given rate, the unit of rate and the rate constant are the same.
(a) zero order reaction
(b) first order reaction
(c) second order reaction
(d) third order reaction

18 / 25
The number of molecules of the reactants involved in a single stage of the reaction indicates
(a) the order of the reaction
(b) the molecularity of the reaction
(c) the rapid step of the reaction mechanism, and
(d) the reaction half-life.

19 / 25
For a unimolecular reaction,
(a) the slowest step’s order and molecularity are both one
(b) the reaction’s molecularity can be zero, one, or two;
(c) the reaction’s molecularity can only be determined experimentally
(d) more than one reacting species are engaged in one step.

20 / 25
The overall rate of a reaction is determined by
(a) the rate of fastest intermediate step
(b) the sum total of the rates of all intermediate steps
(c) the average of the rates of all the intermediate steps
(d) the rate of slowest intermediate step

21 / 25
A first order reaction has a half-life length of 10 minutes. In 100 minutes, what proportion of the response will be completed?
( a) 25%
(b) 50%
(c) 99.9%
(d) 75%

22 / 25
For a 30 percent breakdown, a first order reaction takes 40 minutes. What will t_1/2be?
(a) 77.7 min
(b) 52.5 min
(c) 46.2 min
(d) 22.7 min

23 / 25
The rate constant of a first order reaction is 1.15 10^-3s-1. How long will it take to decrease 5 g of this reactant to 3 g?
(a) 444 seconds
(b) 400 seconds
(c) 528 seconds
(d) 669 seconds

24 / 25
A straight line is drawn when log (a – x) is plotted against time t. This shows that the response is of order
(a) zero
(b) first
(c) second
(d) third

25 / 25
In a chemical reaction, the activation energy is defined as
(a) the difference between the energies of the reactants and products, and
(b) the sum of the energies of the reactants and products.
(c) the difference between the average energy of reactants and products and the energy of the intermediate complex
(d) the difference between the energy of the intermediate complex and the average energy of the reactants

Your score is
The average score is 32%
0%

Post Views: 120

Report a question

🧪Chemical Kinetics – 25 MCQ Quiz

Related Posts

Leave a Comment Cancel Reply