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Chemistry - Chemical Kinetics

Practise 43 WBJEE previous year questions on Chemical Kinetics, compiled from papers spanning 2009 to 2026. Each question is pulled directly from the actual exam paper it appeared in, so you're practising in the exact style and difficulty WBJEE tests.

Chemical Kinetics has been asked in 16 of the 18 years of WBJEE papers analysed (2009–2026), with 43 questions in all. 44% of them were easy, 47% moderate and 9% tough. Most of its questions came from 2014, with 8 questions that year. In the last three years (2024–2026) it had 7 questions across 3 papers, about 2.3 per paper.

The chapter's 6 topics are not weighted equally: Integrated rate laws (12 questions, 28%), Arrhenius theory (10 questions, 23%), and Rate law and rate constant (9 questions, 21%) have been asked the most. Integrated rate laws has also led over the last five years, with 5 questions. Integrated rate laws has produced the most tough questions (2).

  1. 1In a first order reaction the concentration of reactant decreases from moles lit to moles lit in s. The rate constant of the reaction is (ap2026Integrated rate laws
  2. 2An organic compound undergoes first order decomposition. The time taken for its decomposition to th and th of its initial concentration are 2026Integrated rate laws
  3. 3For 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 rea2025Integrated rate laws
  4. 4An egg takes 4.0 minutes to boil at sea level where the boiling point of water is , where as it takes 8.0 minutes to boil on a mountain top 2025Arrhenius theory
  5. 5Which of the following statements is true about equilibrium constant and rate constant of a single step chemical reaction?2024Arrhenius theory
  6. 6After the emission of a -particle followed by an -particle from , the number of neurons in the atom is2024Parallel and Sequencial rate laws
  7. 7For a first order reaction with rate constant , the slope of the plot of log (reactant concentration) against time is2024Integrated rate laws
  8. 8Which of the following would give a linear plot? (\(k\) is the rate constant of an elementary reaction and \( {T}\) is temp. in absolute sca2023Arrhenius theory
  9. 9For the reaction \(A+B C\), we have the following data: \( {array}{|c|c|c|} {array}{c} { Initial concentration of } \\ {A} { (in molarity) }2023Rate law and rate constant
  10. 10If in case of a radio isotope the value of half-life \( (T_{1/2} )\) and decay constant \(( )\) are identical in magnitude, then their value2023Integrated rate laws
  11. 11Under the same reaction conditions, initial concentration of of a substance becomes half in and 20 s through first-order and zero-order kine2021Rate law and rate constant
  12. 12For a reaction , when concentration of alone is doubled, rate does not change and when concentrations of both and is doubled, rate increases2020Rate law and rate constant
  13. 13Consider the following two first order reactions occurring at 298 K with same initial concentration of :(1) rate constant, (2) ; half-life, 2019Integrated rate laws
  14. 14The half-life period of is 60 days. The radioactivity after 180 days will be2019Integrated rate laws
  15. 15Consider, the radioactive disintegration , The sequence of emission can be2019Arrhenius theory
  16. 16The kinetic study of a reaction like at provides the following curve, where concentration is taken in mol and time in min. Identify the corr2019Rate law and rate constant
  17. 17The half-life of is 5760 years. For a sample of , the time taken to change to is2018Integrated rate laws
  18. 18The nucleus accepts an orbital clectron to yield.2018Arrhenius theory
  19. 19is a radio-isotope labelled organic compound. decays by positron emission. The product resulting on decay is2017Parallel and Sequencial rate laws
  20. 20An element loses one and two particle in three successive stages. The resultibg element will be2016Parallel and Sequencial rate laws
  21. 21For the reaction , the reaction rate is doubled, if the concentration of is doubled. The rate is increased by four times When concentrations2015Methods to determine order of reaction
  22. 22The increase in rate constant of a chemical reaction with increasing temperature is (are) due to the fact(s) that2015Arrhenius theory
  23. 23During the emission of a positron from a nucleus, the mass number of the daughter element remains the same but the atomic number2014Parallel and Sequencial rate laws
  24. 24is always accompanied by2014Parallel and Sequencial rate laws
  25. 25An atomic nucleus having low ratio tries to find stability by2014Parallel and Sequencial rate laws
  26. 26\({ }_{98} {Cf}^{246}\) was formed along with a neutron when an unknown radioactive substance was bombarded with \({ }_{6} {C}^{12}\). The u2014Parallel and Sequencial rate laws
  27. 27The rate of a certain reaction is given by, rate . The rate increases 100 times when the pH changes from 3 to 1 . The order of the reaction 2014Rate law and rate constant
  28. 28The correct statement regarding the following energy diagrams is2014Arrhenius theory
  29. 29Among the following compounds, the onele that gives (give) effervescence with aqueoug solution is (are)2014Arrhenius theory
  30. 30A piece of wood from an archaeological sample has 5.0 counts min per gram of while a fresh sample of wood has a count of . If half-life of i2014Integrated rate laws
  31. 31Acid catalysed hydrolysis of ethyl acetate follows a pseudo-first order kinetics with respect to ester. If the reaction is carried out with 2013Rate law and rate constant
  32. 32For a chemical reaction at the activation energy is . The ratio of the rate constants at to that of at will be2013Arrhenius theory
  33. 33The half-life for decay of -emission is . The fraction of decays, in a sample that is 22920 yr old, would be2013Rate law and rate constant
  34. 34Consider the following reaction for The expression for the rate of reaction in terms of the rate of change of partial pressure of reactant a2013Rate of reaction
  35. 35^{24}$ is radioactive and it decays to2012Parallel and Sequencial rate laws
  36. 36Which one of the following is wrong about molecularity of a reaction?2012Rate of reaction
  37. 37In the hydrolysis of an organic chloride in presence of large excess of water;2010Methods to determine order of reaction
  38. 38For a reversible chemical reaction where the forward process is exothermic, which of the following statements is correct?2010Arrhenius theory
  39. 39Radioactivity of a sample ( ) decreases after 10 years. What will be the half life of the sample?2010Integrated rate laws
  40. 40If number of radioatoms are present at time , the following expression will be a constant :2009Rate law and rate constant
  41. 41The following graph shows how (half-life) of a reactant changes with the initial reactant concentration . The order of the reaction will be 2009Rate law and rate constant
  42. 42The time taken for completion of a first order reactin is 20 mins. Then, for completion, the reaction will take2009Integrated rate laws
  43. 43The half-life of a radioactive element is 10 hours. How much will be left after 4 hours in atom sample?2009Integrated rate laws

Frequently Asked Questions

1.How many questions are available for Chemical Kinetics?

This chapter includes 43 questions compiled from WBJEE papers spanning 2009 to 2026.

2.Are these questions only from WBJEE, or from other exams too?

These are WBJEE questions specifically for the Chemical Kinetics chapter. Questions from other exams like JEE Main or NTA Abhyas (JEE Main) are organised separately under their respective exam sections.

3.Is Chemical Kinetics an important chapter for WBJEE Chemistry?

Chemical Kinetics has appeared in 16 of the 18 years of WBJEE papers covered here, with 43 questions across 16 papers - about 3 per paper it appears in.

4.What is the difficulty level of Chemical Kinetics questions in WBJEE?

Of the 43 questions analysed for this chapter, 44% are easy, 47% moderate and 9% tough. 2014 had the most, with 8 questions.

5.Which topics in Chemical Kinetics should I focus on?

These topics have carried the most weightage in Chemical Kinetics:

  • Integrated rate laws - 12 questions (28%)
  • Arrhenius theory - 10 questions (23%)
  • Rate law and rate constant - 9 questions (21%)
  • Integrated rate laws has produced the most tough questions (2).
6.Is Chemical Kinetics's weightage in WBJEE going up or down?

Across all 16 papers analysed, Chemical Kinetics has averaged about 2.7 questions per paper. In the last three years (2024–2026), that average has stayed about the same, at about 2.3 questions per paper. Use the year-wise numbers on this page for the exact trend before you decide how much time to give it.