Chemical Kinetics – MCQs (NEET Style)
Q1. The rate of a chemical reaction is defined as the change in:
A. Pressure per unit volume
B. Concentration of reactant per unit time
C. Temperature per unit time
D. Volume per unit pressure
Q2. Which of the following statements about reaction rate is correct?
A. Rate of reaction increases with decrease in concentration
B. Rate is always constant for all reactions
C. Rate is generally proportional to concentration of reactants
D. Rate depends only on product formed
Q3. A reaction is said to be first order if:
A. Rate ∝ [A]²
B. Rate ∝ [A]
C. Rate ∝ [A]⁰
D. Rate ∝ [B]²
Q4. Which of the following factors does not affect the rate of a reaction?
A. Concentration of reactants
B. Temperature
C. Catalyst
D. Color of reactants
Q5. Increasing the concentration of reactants generally:
A. Decreases the frequency of collisions
B. Increases the frequency of collisions
C. Decreases the activation energy
D. Has no effect on rate
Q6. For a zero-order reaction, the rate of reaction is:
A. Independent of concentration
B. Directly proportional to concentration
C. Proportional to the square of concentration
D. Proportional to the inverse of concentration
Q7. The order of reaction with respect to a reactant is determined experimentally because:
A. It can be calculated from stoichiometry
B. It is always equal to the molecularity
C. It is not necessarily equal to stoichiometric coefficient
D. It depends on temperature only
Q8. If the rate of reaction doubles when the concentration of reactant is doubled, the order of reaction is:
A. 1
B. 2
C. 0
D. 3
Q9. The overall order of the reaction 2A+B→Products, if rate law is Rate = k[A][B]², is:
A. 1
B. 2
C. 3
D. 4
Q10. In a first-order reaction, the half-life:
A. Increases with increase in initial concentration
B. Decreases with increase in initial concentration
C. Is independent of initial concentration
D. Becomes zero at high concentration
Q11. For a second-order reaction, the integrated rate law is:
A. [A] = [A]₀ – kt
B. ln[A] = ln[A]₀ – kt
C. 1/[A] = 1/[A]₀ + kt
D. [A]² = [A]₀² – kt
Q12. The slope of a plot of [A] vs. time for a zero-order reaction is:
A. Positive
B. Negative
C. Zero
D. Depends on initial concentration
Q13. The slope of a plot of ln[A] vs. time for a first-order reaction is:
A. +k
B. –k
C. 0
D. Depends on [A]₀
Q14. The unit of rate constant k for a zero-order reaction is:
A. s⁻¹
B. L mol⁻¹ s⁻¹
C. mol L⁻¹ s⁻¹
D. L² mol⁻² s⁻¹
Q15. Which reaction is an example of pseudo-first-order reaction?
A. Hydrolysis of sucrose with large excess of water
B. Combustion of hydrogen
C. Decomposition of potassium chlorate
D. Neutralization of acid by base
Q16. The rate of a chemical reaction depends on:
A. Orientation of molecules
B. Energy of collisions
C. Frequency of collisions
D. All of the above
Q17. The activation energy of a reaction is:
A. Energy released per mole
B. Minimum energy required for reaction
C. Difference in energy of products and reactants
D. Proportional to temperature
Q18. In Arrhenius equation k=Ae−Ea/RT, “A” is called:
A. Activation energy
B. Pre-exponential factor or frequency factor
C. Rate constant
D. Equilibrium constant
Q19. A catalyst:
A. Increases the activation energy
B. Provides an alternate pathway with lower activation energy
C. Changes the equilibrium position
D. Is consumed in the reaction
Q20. Which of the following reactions is second-order?
A. Rate = k[A]²
B. Rate = k[A]
C. Rate = k
D. Rate = k[A][B][C]
Q21. In a first-order reaction, the time required for the concentration to reduce to one-fourth is:
A. Equal to t½
B. Twice t½
C. Three times t½
D. Four times t½
Q22. For a first-order reaction, a plot of 1/[A] vs. time gives:
A. Straight line
B. Exponential curve
C. Parabola
D. Hyperbola
Q23. The molecularity of a reaction is:
A. Determined experimentally
B. Number of molecules reacting in an elementary step
C. Same as order of reaction always
D. Independent of reaction mechanism
Q24. Which method can be used to determine rate of reaction?
A. Measuring change in concentration with time
B. Measuring pressure change for gases
C. Using colorimetry for colored solutions
D. All of the above
Q25. The decomposition of H₂O₂ in presence of MnO₂ is:
A. Zero-order reaction
B. First-order reaction
C. Second-order reaction
D. Third-order reaction
Q26. In a reaction A+B→C, rate law is Rate = k[A][B]. Doubling [A] and halving [B] changes rate by:
A. No change
B. Half
C. Double
D. Quadruple
Q27. Which of the following affects the frequency factor in Arrhenius equation?
A. Orientation of molecules
B. Temperature
C. Pressure
D. Catalyst only
Q28. The decomposition of N₂O₅ is:
A. First-order reaction
B. Second-order reaction
C. Zero-order reaction
D. Depends on temperature only
Q29. If a reaction is zero-order, the concentration vs. time graph is:
A. Exponential
B. Linear decreasing
C. Linear increasing
D. Hyperbolic
Q30. Half-life of second-order reaction is:
A. Independent of initial concentration
B. Inversely proportional to initial concentration
C. Directly proportional to initial concentration
D. Zero
Q31. Which is true for rate constant of a reaction?
A. It increases with temperature
B. It decreases with temperature
C. Independent of temperature
D. Depends on initial concentration
Q32. The iodide-catalyzed decomposition of H₂O₂ follows:
A. Zero-order kinetics
B. First-order kinetics
C. Pseudo-first-order kinetics
D. Second-order kinetics
Q33. In the reaction 2NO+O2→2NO2, molecularity is:
A. 1
B. 2
C. 3
D. 4
Q34. The units of rate constant for a third-order reaction are:
A. L² mol⁻² s⁻¹
B. L mol⁻¹ s⁻¹
C. s⁻¹
D. mol L⁻¹ s⁻¹
Q35. The reaction A→B+C shows constant rate independent of [A]. Its order is:
A. Zero
B. First
C. Second
D. Third
Q36. The slope of 1/[A] vs time for a second-order reaction is:
A. k
B. –k
C. Zero
D. Depends on [A]₀
Q37. A reaction with order 1 w.r.t A and 2 w.r.t B has overall order:
A. 1
B. 2
C. 3
D. 4
Q38. In a reaction, if Ea is very large, the reaction:
A. Is very fast
B. Is very slow
C. Is independent of temperature
D. Becomes zero-order
Q39. The rate of reaction doubles for a 10°C rise in temperature. This is approximately explained by:
A. Arrhenius equation
B. Collision theory
C. Both A and B
D. Neither
Q40. The activation energy can be determined from:
A. Slope of ln k vs 1/T plot
B. Intercept of ln k vs 1/T plot
C. Half-life of reaction
D. Concentration graph
Q41. Which of the following is true for pseudo-first-order reaction?
A. One reactant is in large excess
B. Rate depends on all reactants equally
C. Reaction becomes zero-order
D. Rate constant changes with concentration
Q42. Rate constant k is independent of:
A. Temperature
B. Catalyst
C. Pressure
D. None
Q43. Which statement is true for a catalyst?
A. It increases the equilibrium constant
B. It lowers the activation energy
C. It is consumed in reaction
D. It slows down the reaction
Q44. In collision theory, only collisions with:
A. Maximum kinetic energy
B. Minimum energy equal to Ea and proper orientation lead to reaction
C. Any energy lead to reaction
D. Low energy lead to reaction
Q45. For a reaction 2A→B, rate = k[A]². The reaction is:
A. First-order
B. Second-order
C. Zero-order
D. Third-order
Q46. Half-life of first-order reaction is 20 min. Time for concentration to reduce to 1/8 is:
A. 20 min
B. 40 min
C. 60 min
D. 80 min
Q47. Which of the following is correct for zero-order reaction?
A. t½ ∝ 1/[A]₀
B. t½ independent of [A]₀
C. Rate ∝ [A]
D. ln[A] vs t is linear
Q48. The units of rate constant for first-order reaction:
A. s⁻¹
B. L mol⁻¹ s⁻¹
C. mol L⁻¹ s⁻¹
D. L² mol⁻² s⁻¹
Q49. Reaction rate depends on:
A. Concentration
B. Temperature
C. Catalyst
D. All of the above
Q50. Which reaction is faster at higher temperature?
A. Reaction with high Ea
B. Reaction with low Ea
C. Both equally
D. Independent of Ea
Q51. Molecularity is:
A. Always equal to order
B. Number of molecules in elementary step
C. Determined experimentally for complex reactions
D. Always 1
Q52. Which graph is linear for first-order reaction?
A. [A] vs t
B. ln[A] vs t
C. 1/[A] vs t
D. t½ vs t
Q53. The rate constant doubles when temperature increases from 300 K to 310 K. This is consistent with:
A. Collision theory
B. Arrhenius equation
C. Both
D. Neither
Q54. Which of the following reactions is an example of first-order?
A. Radioactive decay
B. Combustion of hydrogen
C. Decomposition of H₂O₂ on platinum
D. Neutralization reaction
Q55. The reaction 2NO+O2→2NO2 is third-order overall. Which is true?
A. First-order w.r.t NO, second w.r.t O₂
B. Second-order w.r.t NO, first w.r.t O₂
C. First-order w.r.t both
D. Zero-order
Q1. B – Rate is defined as change in concentration per unit time.
Q2. C – Reaction rate is generally proportional to reactant concentrations.
Q3. B – First-order means rate ∝ [A].
Q4. D – Color has no effect on chemical reaction rate.
Q5. B – Increasing concentration increases collision frequency → rate increases.
Q6. A – Zero-order: rate is independent of concentration.
Q7. C – Order is experimentally determined; not always equal to stoichiometry.
Q8. A – Doubling [A] doubles rate → first-order.
Q9. C – Overall order = 1 + 2 = 3.
Q10. C – Half-life of first-order reaction is independent of [A]₀.
Q11. C – Second-order integrated rate law: 1/[A] = 1/[A]₀ + kt.
Q12. B – Zero-order: [A] vs t is a straight line with negative slope.
Q13. B – Slope of ln[A] vs t for first-order = –k.
Q14. C – Unit of k (zero-order) = mol L⁻¹ s⁻¹.
Q15. A – Large excess of water makes it pseudo-first-order.
Q16. D – Rate depends on frequency, energy, and orientation of collisions.
Q17. B – Activation energy is the minimum energy required for reaction.
Q18. B – “A” is the frequency factor in Arrhenius equation.
Q19. B – Catalyst lowers activation energy, does not get consumed.
Q20. A – Rate = k[A]² → second-order.
Q21. C – For first-order, t₁/₄ = 2 × t½.
Q22. A – Second-order: 1/[A] vs time gives straight line.
Q23. B – Molecularity is number of molecules involved in elementary step.
Q24. D – All listed methods are valid to determine reaction rate.
Q25. A – Catalyzed decomposition of H₂O₂ is zero-order (on catalyst surface).
Q26. B – Rate ∝ [A][B]; doubling [A] and halving [B] → rate unchanged (2 × 0.5 =1).
Q27. A – Frequency factor depends on molecular orientation and collisions.
Q28. A – Decomposition of N₂O₅ is first-order.
Q29. B – Zero-order: concentration decreases linearly with time.
Q30. B – t½ for second-order ∝ 1/[A]₀.
Q31. A – Rate constant increases with temperature.
Q32. C – Hydrolysis of H₂O₂ with iodide is pseudo-first-order.
Q33. C – 2NO + O₂ → 2NO₂, molecularity = 3.
Q34. A – Third-order: unit of k = L² mol⁻² s⁻¹.
Q35. A – Rate independent of [A] → zero-order.
Q36. A – Slope of 1/[A] vs t for second-order = k (positive).
Q37. C – Overall order = 1 + 2 = 3.
Q38. B – High activation energy → slow reaction.
Q39. C – Both Arrhenius equation and collision theory explain temperature effect.
Q40. A – Activation energy Ea = slope of ln k vs 1/T plot (–Ea/R).
Q41. A – One reactant in large excess → pseudo-first-order.
Q42. D – Rate constant depends on temperature, catalyst, pressure (for gases).
Q43. B – Catalyst lowers activation energy; does not affect equilibrium.
Q44. B – Only collisions with sufficient energy and proper orientation lead to reaction.
Q45. B – Rate = k[A]² → second-order.
Q46. C – First-order: t₁/₈ = 3 × t½ = 3 × 20 = 60 min.
Q47. A – Zero-order: t½ ∝ 1/[A]₀.
Q48. A – First-order: unit of k = s⁻¹.
Q49. D – Rate depends on concentration, temperature, and catalyst.
Q50. B – Low Ea → reaction faster at higher temperature.
Q51. B – Molecularity = number of molecules in elementary step.
Q52. B – First-order: ln[A] vs t is linear.
Q53. C – Both collision theory and Arrhenius equation explain doubling of rate.
Q54. A – Radioactive decay is a first-order process.
Q55. B – Rate law: Rate ∝ [NO]²[O₂] → first-order O₂, second-order NO.
Disclaimer:
All MCQs are educational, and created for practice purposes only. They are based on NCERT and NEET syllabus and not official NEET questions.