Free Reaction Kinetics MCQs with Answers
573 Reaction Kinetics MCQs from Chemistry, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Reaction kinetics relates reaction rate to concentration, temperature, surface area and catalysts. Questions cover rate laws, reaction order, rate constants, activation energy and the activated complex, including how a catalyst lowers the activation energy without changing the overall energy change or equilibrium position.
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573 questions · page 16 of 29
- A. Increases as the reaction proceeds
- B. Decreases as the reaction proceeds
- C. Remains the same as the reaction proceeds
- D. May decrease or increase as the reaction proceeds
Explanation: As the reaction proceeds, the rate of reaction may decrease due to factors like the depletion of reactants or the accumulation of…
Correct answer: Decreases as the reaction proceeds- A. Decrease in activation energy of reaction
- B. Decrease in the number of collision between molecules of reactants
- C. Increase in activation energy of molecules of reactants
- D. Increase in number of effective collision
Explanation: When the temperature increases by 10°C, the rate of reaction doubles because of an increase in effective collisions.
Correct answer: Increase in number of effective collision- A. Ea of exothermic reaction in the forward reaction is less than that of backward reaction
- B. Ea of endothermic reaction in the forward direction is greater than that of reverse reaction
- C. Ea is directly proportional to k
- D. Ea is independent of temperature
Explanation: The activation energy and the rate constant have an inverse relation. So, the C option is our correct answer since the relation written is…
Correct answer: Ea is directly proportional to k- A. 1st order reaction
- B. 2nd order reaction
- C. Zero order reaction
- D. 3rd order reaction
Explanation: r=k[A]x [B]yIn this reaction r= rate of reaction and k = rate constant, [A] and B] are the concentration of the reactant A and B .
Correct answer: Zero order reaction- A. It determines mechanism of reaction
- B. It is determined experimentally
- C. It is associated with rate equation
- D. it is always equal to molecularity
Explanation: The order of a reaction can indeed be equal to its molecularity. The order of a reaction refers to the sum of the exponents in the rate…
Correct answer: it is always equal to molecularity306. In which of the following order of reaction, the half-life is independent of initial concentration?
- A. Zero order
- B. 1st order
- C. 2nd order
- D. 3rd order
Explanation: In a first-order reaction, the rate of the reaction is directly proportional to the concentration of the reactant.
Correct answer: 1st order- A. Concentration of reactants
- B. Molecularity
- C. Catalyst
- D. Temperature
Explanation: Molecularity refers to the number of molecules or ions that participate as reactants in an elementary reaction step.
Correct answer: Molecularity- A. Change the enthalpy
- B. Change the entropy
- C. Change the nature of products
- D. Change the activation energy
Explanation: Option D is the most accurate statement. A catalyst provides an alternative reaction pathway with a lower activation energy.
Correct answer: Change the activation energy309. The experimental relationship between rate of reaction and concentration of reactant is called:
- A. Rate Law
- B. Hess's Law
- C. Law of mass action
- D. Le-Chateliar's principle
Explanation: The rate law describes the relationship between the rate of a chemical reaction and the concentrations of its reactants.
Correct answer: Rate Law- A. Concentration of reactants
- B. Pressure
- C. Temperature
- D. Surface area
Explanation: Temperature has a significant impact on the specific rate constant. The Arrhenius equation describes how the rate constant changes with…
Correct answer: Temperature- A. A
- B. B
- C. C
- D. D
Explanation: Heterogenous catalysis: The catalysis in which reactants and catalyst are in different phase.Homogenous catalysis: The catalysis in which…
Correct answer: A- A. Zero order
- B. 1st order
- C. 2nd order
- D. 3rd order
Explanation: In a second-order reaction, the rate of reaction is proportional to the square of the concentration of the reactant.
Correct answer: 2nd order- A. P is a catalyst in this reaction
- B. P molecules do not possess sufficient energy to react
- C. The rate of reaction is independent of conc. of Q
- D. The rate of reaction is independent of conc. of P
Explanation: If a reaction is of zero order with respect to P, it means that changes in the concentration of P do not affect the rate of the reaction.
Correct answer: The rate of reaction is independent of conc. of P- A. rate =k[RCI]2
- B. rate =k[RCI] [OH-]2
- C. rate =k[RCI] [OH-1]
- D. rate =k[RCI]
Explanation: Step 1 (Rate-Determining Step):(CH3)3CCl → (CH3)3C+ + Cl-Step 2:(CH3)3C+ + OH- → (CH3)3COH.Option D proposes that the rate is proportional…
Correct answer: rate =k[RCI]- A. s-1
- B. mol.dm-3s-1
- C. mol dm-1s
- D. mol-1dm1s
Explanation: rate has units of, for example, mol dm^-3 s^-1 (concentration per unit time).k (rate constant) needs to have units that cancel out the…
Correct answer: s-1- A. 3 hours
- B. 6 hours
- C. 4 hours
- D. 8 hours
Explanation: Option D is correct.The half-life of a radioactive isotope is the time it takes for half of the radioactive atoms in a sample to decay.
Correct answer: 8 hours- A. mol dm-3s-1
- B. mol-2 dm6s-1
- C. mol-1 dm3s-1
- D. mol-1s-1
Explanation: Option C is correct.The rate constant (k) for a second-order reaction has units of mol-1 dm3 s-1.
Correct answer: mol-1 dm3s-1- A. 2
- B. 8
- C. 3
- D. 4
Explanation: Option D is correct.The rate of reaction of a gaseous reaction is proportional to the partial pressure of the reactants.
Correct answer: 4- A. 5 min
- B. 10 min
- C. 15 min
- D. 20 min
Explanation: Option C is correct.To determine how long it will be before the number of atoms of isotope "G" equals the number of atoms of isotope "H,"…
Correct answer: 15 min- A. t1/2 = ln(2) / k
- B. t1/2 = 1 / k[A]
- C. t1/2 = 1 / k[A]²
- D. None of these
Explanation: Option B is correct.This is for second order.of reaction.For Second order rate = k[A]². We know that half live= t1/2 =1/a ,t1/2 = 1 / k[A] .
Correct answer: t1/2 = 1 / k[A]