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 26 of 29
- A. Concentration of reactants decrease
- B. Concentration of product decreases
- C. The order of reaction changes
- D. Temperature of the system changes
Explanation: The reaction rate in forward direction decreases with the passage of time because the concentration of reactants decreases.
Correct answer: Concentration of reactants decrease- A. During a chemical reaction, the particles must collide for a reaction to occur.
- B. Reaction between the colliding particles can only take place if they possess the activation energy upon collision.
- C. Only collisions with the correct spatial orientation are effective in causing a reaction.
- D. All of the above statements are correct.
Explanation: All the given statements are correct assumptions of collision theory.Option A: Acknowledges that collisions are fundamental to initiating…
Correct answer: All of the above statements are correct.- A. The rate of reaction increases with decreasing activation energy.
- B. The rate of reaction is independent of the activation energy.
- C. The rate of reaction decreases with decreasing activation energy.
- D. The rate of reaction increases with increasing activation energy.
Explanation: The rate of a chemical reaction is inversely related to the activation energy.
Correct answer: The rate of reaction increases with decreasing activation energy.- A. These are in pure crystalline state
- B. The activity of enzyme catalyst is inhibited by poison
- C. Enzyme catalytic reactions have maximum rate at optimum temperature
- D. All of these
Explanation: The correct answer is D: All of these. Enzyme catalysts can exist in a pure crystalline state, although this is not a feature of all…
Correct answer: All of these- A. The rate of reaction increases as the reaction proceeds
- B. The rate of reaction decreases as the reaction proceeds
- C. The rate of reaction remains the same as the reaction proceeds
- D. The rate of reaction may decrease or increase as the reaction proceeds
Explanation: The rate of reaction typically decreases as the reaction progresses due to the depletion of reactants and the accumulation of products.
Correct answer: The rate of reaction decreases as the reaction proceeds- A. It does not determines the mechanism of reaction
- B. It is determined experimentally
- C. It is associated with the rate equation
- D. It is always equal to molecularity
Explanation: The statement that the order of a reaction is always equal to its molecularity is incorrect.
Correct answer: It is always equal to molecularity507. 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 Chatelier's Principle
Explanation: The Rate Law is the correct choice because it defines the mathematical relationship between the concentration of reactants and the rate of…
Correct answer: Rate Law- A. A. The oxidation of sulfur dioxide (SO2) to sulfur trioxide (SO3) using vanadium(V) oxide (V2O5) as a catalyst.
- B. B. The esterification of acetic acid with ethanol using sulfuric acid (H2SO4) as a catalyst.
- C. C. The decomposition of ozone (O3) using nitric oxide (NO) as a catalyst.
- D. D. The hydrogenation of ethylene (C2H4) using a platinum catalyst.
Explanation: Heterogeneous catalysis occurs when the catalyst and the reactants are in different phases.
Correct answer: A. The oxidation of sulfur dioxide (SO2) to sulfur trioxide (SO3) using vanadium(V) oxide (V2O5) as a catalyst.- A. A. Molecularity of a reaction is always an integer value.
- B. B. The order of a reaction is determined experimentally and can be a fraction.
- C. C. Molecularity is applicable to elementary reactions only.
- D. D. Molecularity can be zero, and order of reaction must be a positive integer.
Explanation: The correct answer is D. Molecularity refers to the number of molecules involved in an elementary reaction and must be a positive integer.
Correct answer: D. Molecularity can be zero, and order of reaction must be a positive integer.- A. Increases only the rate of the forward reaction
- B. Increases only the rate of the reverse reaction
- C. Increases the rate of the forward reaction but decreases the rate of the reverse reaction
- D. Increases the rate of both the forward and reverse reactions equally
Explanation: Option D is correct. Catalysts work by lowering the activation energy required for a reaction to proceed, which affects both the forward…
Correct answer: Increases the rate of both the forward and reverse reactions equally- A. The concentration of the reactants increases
- B. The activation energy for the reaction decreases
- C. Collision frequency and energy increase
- D. All of the above
Explanation: The correct answer is that collision frequency and energy increase. When temperature increases, the kinetic energy of molecules increases…
Correct answer: Collision frequency and energy increase- A. Higher than average rate
- B. Lower than average rate
- C. Equal to the average rate
- D. None of these
Explanation: At the start of a chemical reaction, the concentration of reactants is highest, which increases the frequency of collisions between…
Correct answer: Higher than average rate- A. Rate of reaction
- B. Direction of reaction
- C. Factors affecting rate of reaction
- D. Both A & C
Explanation: Reaction kinetics is an essential branch of chemistry that examines both the rate of chemical reactions and the factors affecting these…
Correct answer: Both A & C- A. Decomposition of N2O5
- B. Formation of FeI2
- C. Formation of Glucose in plants
- D. Chlorination of methane in sunlight
Explanation: The correct answer is the formation of FeI2, as it is a second-order reaction where the rate is determined by the concentrations of both…
Correct answer: Formation of FeI2- A. 1
- B. 1.5
- C. 2.5
- D. Zero
Explanation: The order of a reaction is determined by the sum of the exponents of the concentration terms in the rate law.
Correct answer: 1.5- A. Lowering the activation energy
- B. Increasing the activation energy
- C. Lowering the frequency or effectiveness of collisions between reactive molecules
- D. Increasing the frequency or effectiveness of collisions between reactive molecules
Explanation: Increasing the temperature increases the kinetic energy of molecules, which leads to more frequent and effective collisions between…
Correct answer: Increasing the frequency or effectiveness of collisions between reactive molecules- A. A: Concentration of the reactant
- B. B: Time
- C. C: Concentration of the product
- D. D: Temperature
Explanation: The rate constant of a first-order reaction is primarily dependent on temperature.
Correct answer: D: Temperature- A. H (Enthalpy)
- B. E (Energy of Reactants or Products)
- C. Ea (Activation Energy)
- D. Collision frequency
Explanation: The correct answer is Option C: Ea (Activation Energy). A catalyst functions by offering an alternative reaction pathway with a reduced…
Correct answer: Ea (Activation Energy)- A. CH4 + Cl2
- B. CH3COOH + C2H5OH
- C. AgNO3 + NaCl
- D. C + 2H2
Explanation: The correct answer is Option C: AgNO3 + NaCl. This reaction is a classic example of a double displacement reaction where two soluble ionic…
Correct answer: AgNO3 + NaCl- A. s-1
- B. mol dm-3s-1
- C. mol-1dm3s-1
- D. mol-2dm+6s-1
Explanation: For a second-order reaction, the rate law is: Rate = k [A]^2Units of Rate = mol L^-1 s^-1Units of [A] = mol L^-1Rearranging the rate law:k…
Correct answer: mol-1dm3s-1