Kinetics MCQs

  1. Chemical kinetics deals with:
    A) Equilibrium
    B) Rate of reaction
    C) Structure of atom
    D) Thermodynamics
    Answer: B
  2. Rate of reaction is defined as:
    A) Change in temperature
    B) Change in concentration per unit time
    C) Change in pressure
    D) Change in volume
    Answer: B
  3. Unit of rate of reaction is:
    A) mol
    B) mol/L
    C) mol L⁻¹ s⁻¹
    D) s⁻¹
    Answer: C
  4. Order of reaction is:
    A) Always whole number
    B) Sum of powers of concentration
    C) Always 1
    D) Independent of rate
    Answer: B
  5. Molecularity refers to:
    A) Number of molecules in rate law
    B) Number of reacting species in a step
    C) Order of reaction
    D) Rate constant
    Answer: B
  6. For zero-order reaction, rate is:
    A) Independent of concentration
    B) Directly proportional
    C) Inversely proportional
    D) Square of concentration
    Answer: A
  7. Unit of zero-order rate constant is:
    A) s⁻¹
    B) mol L⁻¹ s⁻¹
    C) L mol⁻¹ s⁻¹
    D) mol²
    Answer: B
  8. Half-life of zero-order reaction depends on:
    A) Initial concentration
    B) Rate constant only
    C) Temperature only
    D) Pressure
    Answer: A
  9. For first-order reaction, half-life is:
    A) Constant
    B) Depends on concentration
    C) Increases with time
    D) Zero
    Answer: A
  10. Unit of first-order rate constant is:
    A) mol L⁻¹ s⁻¹
    B) s⁻¹
    C) L mol⁻¹ s⁻¹
    D) mol²
    Answer: B
  11. Second-order reaction unit of k is:
    A) s⁻¹
    B) mol L⁻¹ s⁻¹
    C) L mol⁻¹ s⁻¹
    D) L² mol⁻² s⁻¹
    Answer: C
  12. Rate law expression is:
    A) Derived experimentally
    B) Always theoretical
    C) Independent of experiment
    D) Fixed formula
    Answer: A
  13. Catalyst increases reaction rate by:
    A) Increasing temperature
    B) Lowering activation energy
    C) Changing equilibrium
    D) Increasing pressure
    Answer: B
  14. Activation energy is:
    A) Minimum energy required for reaction
    B) Maximum energy
    C) Heat of reaction
    D) Internal energy
    Answer: A
  15. Arrhenius equation relates:
    A) Rate and pressure
    B) Rate constant and temperature
    C) Volume and temperature
    D) Energy and pressure
    Answer: B
  16. Increasing temperature increases rate because:
    A) More collisions
    B) Higher activation energy
    C) Lower pressure
    D) Less energy
    Answer: A
  17. Reaction rate decreases when:
    A) Temperature increases
    B) Concentration increases
    C) Catalyst added
    D) Temperature decreases
    Answer: D
  18. Collision theory explains:
    A) Equilibrium
    B) Reaction rate
    C) Atomic structure
    D) Thermodynamics
    Answer: B
  19. Effective collision requires:
    A) Proper orientation
    B) Low energy
    C) No contact
    D) Zero energy
    Answer: A
  20. Rate constant depends on:
    A) Concentration
    B) Temperature
    C) Pressure
    D) Volume
    Answer: B
  21. Pseudo first-order reaction involves:
    A) Two reactants
    B) One reactant
    C) Excess of one reactant
    D) Zero order
    Answer: C
  22. Graph of zero-order reaction is:
    A) Straight line (concentration vs time)
    B) Curve
    C) Hyperbola
    D) Exponential
    Answer: A
  23. First-order reaction graph is linear for:
    A) [A] vs t
    B) ln[A] vs t
    C) 1/[A] vs t
    D) t vs [A]
    Answer: B
  24. Second-order reaction graph is linear for:
    A) [A] vs t
    B) ln[A] vs t
    C) 1/[A] vs t
    D) t² vs [A]
    Answer: C
  25. Slowest step determines:
    A) Molecularity
    B) Rate of reaction
    C) Equilibrium
    D) Energy
    Answer: B
  26. Reaction mechanism is:
    A) Single step
    B) Sequence of steps
    C) Final product
    D) Rate law
    Answer: B
  27. Intermediate is:
    A) Reactant
    B) Product
    C) Formed and consumed
    D) Catalyst
    Answer: C
  28. Catalyst is regenerated at:
    A) Beginning
    B) Middle
    C) End
    D) Never
    Answer: C
  29. Temperature rise increases rate constant:
    A) Linearly
    B) Exponentially
    C) Logarithmically
    D) Randomly
    Answer: B
  30. Rate law for first-order reaction is:
    A) Rate = k[A]
    B) Rate = k[A]²
    C) Rate = k
    D) Rate = k/[A]
    Answer: A
  31. Rate law for second-order reaction is:
    A) k[A]
    B) k[A]²
    C) k
    D) k/[A]
    Answer: B
  32. Zero-order rate law is:
    A) k[A]
    B) k[A]²
    C) k
    D) k/[A]
    Answer: C
  33. Half-life formula for first-order is:
    A) t₁/₂ = 0.693/k
    B) t₁/₂ = k/0.693
    C) t₁/₂ = [A]/k
    D) t₁/₂ = k[A]
    Answer: A
  34. Doubling concentration doubles rate in:
    A) Zero-order
    B) First-order
    C) Second-order
    D) All
    Answer: B
  35. Doubling concentration quadruples rate in:
    A) Zero-order
    B) First-order
    C) Second-order
    D) Third-order
    Answer: C
  36. Integrated rate law is used to:
    A) Determine order
    B) Find temperature
    C) Find pressure
    D) Find volume
    Answer: A
  37. Rate constant increases with:
    A) Pressure
    B) Temperature
    C) Volume
    D) Mass
    Answer: B
  38. High activation energy means:
    A) Fast reaction
    B) Slow reaction
    C) No reaction
    D) Instant reaction
    Answer: B
  39. Reaction with low Ea is:
    A) Slow
    B) Fast
    C) Impossible
    D) Reversible
    Answer: B
  40. Enzymes act as:
    A) Inhibitors
    B) Catalysts
    C) Reactants
    D) Products
    Answer: B
  41. Increasing surface area increases rate due to:
    A) More collisions
    B) Less energy
    C) Less contact
    D) Low temperature
    Answer: A
  42. Reaction rate is highest at:
    A) Start
    B) Middle
    C) End
    D) Constant
    Answer: A
  43. Rate law depends on:
    A) Stoichiometry
    B) Mechanism
    C) Temperature
    D) Volume
    Answer: B
  44. Reaction order can be:
    A) Fractional
    B) Integer only
    C) Zero only
    D) Negative only
    Answer: A
  45. Molecularity is always:
    A) Fractional
    B) Integer
    C) Zero
    D) Negative
    Answer: B
  46. Arrhenius equation:
    A) k = Ae^(-Ea/RT)
    B) PV = nRT
    C) E = mc²
    D) F = ma
    Answer: A
  47. Increasing catalyst concentration:
    A) Decreases rate
    B) Increases rate
    C) No effect
    D) Stops reaction
    Answer: B
  48. Rate of reaction depends on:
    A) Nature of reactants
    B) Temperature
    C) Catalyst
    D) All
    Answer: D
  49. Reaction mechanism helps to:
    A) Predict rate law
    B) Predict volume
    C) Predict pressure
    D) Predict temperature
    Answer: A
  50. Rate-determining step is:
    A) Fastest step
    B) Slowest step
    C) Middle step
    D) First step
    Answer: B

  1. The rate of a reaction is fastest when concentration is:
    A) Lowest
    B) Zero
    C) Highest
    D) Constant
    Answer: C
  2. Which factor does NOT affect reaction rate?
    A) Temperature
    B) Catalyst
    C) Color
    D) Concentration
    Answer: C
  3. In a first-order reaction, rate depends on:
    A) Square of concentration
    B) Concentration
    C) No concentration
    D) Pressure
    Answer: B
  4. Half-life of second-order reaction depends on:
    A) Initial concentration
    B) Only rate constant
    C) Temperature only
    D) Pressure
    Answer: A
  5. Which reaction has constant rate?
    A) First-order
    B) Second-order
    C) Zero-order
    D) Third-order
    Answer: C
  6. The slope of ln[A] vs time graph equals:
    A) k
    B) -k
    C) 1/k
    D) -1/k
    Answer: B
  7. The slope of 1/[A] vs time graph equals:
    A) k
    B) -k
    C) 1/k
    D) -1/k
    Answer: A
  8. Rate constant is independent of:
    A) Temperature
    B) Catalyst
    C) Concentration
    D) Activation energy
    Answer: C
  9. Arrhenius factor A represents:
    A) Activation energy
    B) Frequency factor
    C) Rate
    D) Temperature
    Answer: B
  10. Activation energy decreases with:
    A) Catalyst
    B) Temperature
    C) Pressure
    D) Volume
    Answer: A
  11. Reaction rate doubles when temperature increases by about:
    A) 1°C
    B) 5°C
    C) 10°C
    D) 50°C
    Answer: C
  12. Reaction mechanism involves:
    A) Only one step
    B) Multiple steps
    C) No steps
    D) Random process
    Answer: B
  13. Elementary reaction is:
    A) Multi-step
    B) Single-step
    C) Complex
    D) Slow
    Answer: B
  14. Order of elementary reaction equals:
    A) Molecularity
    B) Rate
    C) Time
    D) Temperature
    Answer: A
  15. Intermediate species are:
    A) Stable
    B) Final products
    C) Short-lived
    D) Catalysts
    Answer: C
  16. Which is true for catalyst?
    A) Consumed permanently
    B) Changes equilibrium
    C) Lowers activation energy
    D) Increases Ea
    Answer: C
  17. Which graph gives rate constant for first-order reaction?
    A) [A] vs t
    B) ln[A] vs t
    C) 1/[A] vs t
    D) t² vs [A]
    Answer: B
  18. Reaction rate is zero when:
    A) Concentration is zero
    B) Temperature is high
    C) Catalyst added
    D) Pressure high
    Answer: A
  19. Rate law is determined by:
    A) Stoichiometry
    B) Experiment
    C) Theory only
    D) Pressure
    Answer: B
  20. High temperature increases reaction rate due to:
    A) More collisions
    B) Less energy
    C) Low pressure
    D) Less molecules
    Answer: A
  21. A catalyst provides:
    A) New reaction pathway
    B) Higher activation energy
    C) No pathway
    D) Higher pressure
    Answer: A
  22. Reaction order is sum of:
    A) Coefficients
    B) Powers of concentration
    C) Reactants
    D) Products
    Answer: B
  23. Molecularity is defined for:
    A) Overall reaction
    B) Elementary step
    C) Rate law
    D) Equilibrium
    Answer: B
  24. Molecularity can be:
    A) Zero
    B) Fractional
    C) Integer only
    D) Negative
    Answer: C
  25. Order of reaction can be:
    A) Fractional
    B) Negative
    C) Zero
    D) All
    Answer: D
  26. Reaction rate depends on:
    A) Nature of reactants
    B) Temperature
    C) Catalyst
    D) All
    Answer: D
  27. Fast reactions have:
    A) High Ea
    B) Low Ea
    C) No Ea
    D) Infinite Ea
    Answer: B
  28. Slow reactions have:
    A) Low Ea
    B) High Ea
    C) No Ea
    D) Zero Ea
    Answer: B
  29. Rate constant k increases with:
    A) Temperature
    B) Volume
    C) Mass
    D) Pressure
    Answer: A
  30. Arrhenius equation shows exponential relation between:
    A) k and T
    B) k and P
    C) V and T
    D) E and P
    Answer: A
  31. Rate-determining step controls:
    A) Overall rate
    B) Temperature
    C) Volume
    D) Pressure
    Answer: A
  32. Catalyst affects:
    A) Rate
    B) Equilibrium
    C) Product
    D) Temperature
    Answer: A
  33. Which is not a unit of rate constant?
    A) s⁻¹
    B) L mol⁻¹ s⁻¹
    C) mol L⁻¹ s⁻¹
    D) kg
    Answer: D
  34. Reaction order is experimentally found using:
    A) Graph
    B) Theory
    C) Guess
    D) Pressure
    Answer: A
  35. If rate = k[A]²[B], order is:
    A) 2
    B) 3
    C) 1
    D) 4
    Answer: B
  36. Half-life of first-order reaction is independent of:
    A) Initial concentration
    B) Rate constant
    C) Temperature
    D) Catalyst
    Answer: A
  37. Rate of reaction increases with:
    A) Decrease in temperature
    B) Increase in concentration
    C) Decrease in pressure
    D) Decrease in surface area
    Answer: B
  38. Surface area affects reactions involving:
    A) Gases
    B) Liquids
    C) Solids
    D) All
    Answer: C
  39. Increasing pressure increases rate for:
    A) Solids
    B) Liquids
    C) Gases
    D) All
    Answer: C
  40. Reaction rate is maximum at:
    A) Beginning
    B) End
    C) Middle
    D) Constant
    Answer: A
  41. A straight line graph indicates:
    A) Constant rate
    B) Changing rate
    C) Zero rate
    D) Infinite rate
    Answer: A
  42. Integrated rate law helps to find:
    A) Order
    B) Pressure
    C) Volume
    D) Mass
    Answer: A
  43. Catalyst is:
    A) Reactant
    B) Product
    C) Substance that speeds reaction
    D) Inhibitor
    Answer: C
  44. Reaction with multiple steps is:
    A) Simple
    B) Complex
    C) Fast
    D) Slow
    Answer: B
  45. Collision theory requires:
    A) Energy
    B) Orientation
    C) Contact
    D) All
    Answer: D
  46. Effective collision needs:
    A) Correct orientation
    B) Sufficient energy
    C) Both
    D) None
    Answer: C
  47. Rate constant decreases when:
    A) Temperature increases
    B) Temperature decreases
    C) Catalyst added
    D) Pressure increases
    Answer: B
  48. Rate constant is symbolized by:
    A) k
    B) r
    C) t
    D) v
    Answer: A
  49. Unit of rate constant depends on:
    A) Temperature
    B) Order of reaction
    C) Pressure
    D) Volume
    Answer: B
  50. Chemical kinetics studies:
    A) Speed of reactions
    B) Equilibrium
    C) Thermodynamics
    D) Structure
    Answer: A

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