CBSE Class 12 Chemistry Chemical Kinetics Questions Answers

Read and download free pdf of CBSE Class 12 Chemistry Chemical Kinetics Questions Answers. Students and teachers of Class 12 Chemistry can get free advanced study material, revision notes, sure shot questions and answers for Class 12 Chemistry prepared as per the latest syllabus and examination guidelines in your school. Standard 12 students should download this study material which will give them more knowledge for all chapters in Chemistry and all important topics which are scoring and can get you more marks. Students should also download free pdf of Chapter wise Notes for Class 12 Chemistry prepared by school teachers as per the latest NCERT, CBSE, KVS books and syllabus issued this year and also download free worksheets and question papers available here to get higher scores in school exams and tests, also click here for more Study Material for Class 12 Chemistry

CBSE Class 12 Chemistry Chemical Kinetics Questions Answers. There are many more useful educational material which the students can download in pdf format and use them for studies. Study material like concept maps, important and sure shot question banks, quick to learn flash cards, flow charts, mind maps, teacher notes, important formulas, past examinations question bank, important concepts taught by teachers. Students can download these useful educational material free and use them to get better marks in examinations.  Also refer to other worksheets for the same chapter and other subjects too. Use them for better understanding of the subjects. 


1. What do you understand by the rate determining step of a reaction?

2. Find the molecularity of following reaction. RCOOR’ + H2O --------H+→RCOOH + R’OH

3. The rate constant of a reaction is 5.0 X 10-5 L mol-1 min-1. What is the order of the reaction?

4. Why rate of the reaction does not remain constant throughout?

5. What is the order of reaction whose rate constant has the same units as the rate of reaction?

6. Write Arrhenius equation.

7. Define rate constant or specific reaction rate.

8. The reaction A + 3B ----→ 2C obeys the rate equation. Rate = k [A]1/2 [B]3/2.What is the order of this reaction? 

9. What are the units of rate constant for a first order reaction?

10. Give one example of a reaction where order and molecularity are equal.

11. What do you understand by half-life period of a reaction?

12. Hydrolysis of ethyl acetate with NaOH is a reaction of second order while with HCl, it is of first order. Why?

13. What is the effect of adding catalyst on the free energy (ΔG) change of a reaction?

14. The rate of a reaction whose rate law is Rate = k [B]n becomes double on doubling the concentration of B. Find the value n.

15. A reaction is 50% complete in 2 hrs. And 75% complete in 4 hrs. What is the order of reaction?

16. Give one example of a first order reaction.

17. Define threshold energy.

18. The reaction A+B --→ C has zero order. What is the rate equation?

19. Which reactions proceed with constant rate?.

20. How does catalyst affect rate of reaction?

21. . For a chemical reaction represented by R→ P the rate of reaction is denoted by –d [R]/dt or +d[P]/dt . State the significance of plus and minus sign.

22. Express the rate of reaction in terms of disappearance of hydrogen andappearance of ammonia in the given reaction. N2(g) + 3 H2 (g) → 2NH3 (g)

23. Why rate of reaction does not remain constant throughout?

24. Write the unit of first order rate constant of a gaseous reaction if the partial pressure of gaseous reactant is given in bar.

25. What will be the order of reaction, if the rate of reaction does not depend on the concentration of any of the reactant?

26. For the elementary step of a chemical reaction :H2 + I2 →2HI rate of reaction →[H2] [I2]What is the (i) molecularity and (ii) order of the reaction.

27. For a chemical reaction A→ B. The rate of the reaction is given as Rate =k [A]n the rate of the above reaction quadruples when the concentration of A is doubled. What is the value of n?

28. Mention one example of zero order reaction.

29. What is the value of the order of reaction of radioactive decay?

30. Express the relation between the half life period of a reactant and initial concentration for a reaction of nth order.

31. A reaction is 50% complete in 2 hours and 75% complete in 4 hours. What is the order of reaction?  

32. Suggest an appropriate reason for the observation : “On increasing temperature of the reacting system by 10 degrees, the rate of reaction almost doubles or even sometimes becomes five folds.”

33. For a chemical reaction, activation energy is zero and at 300K rate constant is 5.9 × 10-5s–1, what will be the rate constant at 400K?

34. Two reactions occuring at the same temperature have identical values of Ea. Does this ensure that also they will have the same rate constant? Explain.

35. The rate constant of a reaction is given by the expression k = Ae–Ea/RT. Which factor in this expression should register a decrease so that the reaction proceeds rapidly?

36. For a chemical reaction rate constant k = 5.3 × 10-4mol L–1 s–1, what will be the order of reaction?

37. Write the rate law and order for the following reaction :

AB2 + C2→AB2C + C (slow)

AB2 + C→AB2C (Fast)]

38. The conversion of molecules X to Y follows second order kinetics. If concentration of X is increased to 3 times how will it affect the rate of formation of Y.

39. When rate of reaction becomes equal to specific reaction rate.

40. 87.5% of the substance disintegrated in 45 minutes (first order reaction) .What is its Half life.


1. The slowest step in a reaction is known as rate determining step.

2. Molecularity of reaction = 2 (there are two reactant molecules in balanced equation)

3. The order of reaction is 2.

4. Rate of reaction depends upon concentration of reactants which keep on decreasing with time. Hence, rate of reaction does not remain constant throughout.

5. Zero order.

6. Ae-Ea/RT Where,k = Rate constant Ea = Activation energy A = Arrhenius factor

7. When the molar concentration of each reactant is unity, the rate of reaction is called specific

reaction rate.

8. Order =(1/2) + (3/2) = 2

9. s-1

10. For elementary reaction, order and molecularity are same. These reactions are carried out. 

Please click the link below to download CBSE Class 12 Chemistry Chemical Kinetics Questions Answers.



Click to View or Download pdf file
Click for more Chemistry Study Material

Latest NCERT & CBSE News

Read the latest news and announcements from NCERT and CBSE below. Important updates relating to your studies which will help you to keep yourself updated with latest happenings in school level education. Keep yourself updated with all latest news and also read articles from teachers which will help you to improve your studies, increase motivation level and promote faster learning

CBSE Assessment Framework

The Central Board of Secondary Education (CBSE) today, announced a suggested competency-based assessment framework to strengthen India’s existing school education system for secondary level (classes 6-10) and improve the overall learning outcomes of students across...

Class 10 Boards Cancelled Class 12 postponed

Looking to the present situation of the pandemic and school closures, and also taking in account the safety and well-being of the students, it is decided as follows:   1. The Board Exams for Class XIIth to be held from May 4th to June, 14th, 2021 are hereby postponed....

CBSE asks schools to load Class 12 Internal Assessment Marks

This has a reference to the letter no CBSE/COORD/2021 dated 11.02.2021 regarding conduct of the School-Based Assessment (Internal Assessment/Practical/ Project) of Class-XII and uploading the marks by 11.06.2021. It has been observed that some schools have not been...

Latest CBSE Syllabus for 2021 2022 PDF Download

Latest Syllabus for Class 12 for 2021 2022 Latest Syllabus for Class 11 for 2021 2022 Latest Syllabus for Class 10 for 2021 2022 Latest Syllabus for Class 9 for 2021 2022 CBSE has issued the latest syllabus for the academic year 2021 2022 which is applicable for all...

FAQs on Policy for Tabulation of Marks for Class 10 Board Exams

ON POLICY Question.1 How CBSE will declare the result of Class-X? Answer. Results of Class X Board will be declared on the basis of an objective criterion developed by the Board vide Notification no.CBSE/CE/2021 dated 01.05.2021. Question.2. If any candidate is not...

Time management for CBSE students

The first thing to learn about Time Management is that time is theoretical so you can’t really manage it. What you do when you get into time management, is that you manage yourself. You decide what has to be done, when it must be done and how to do it in the stipulated...

Studies Today