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 27 of 29
- A. Will double the reaction rate
- B. Will increase the reaction rate
- C. Will decrease the reaction rate
- D. Will not alter the concentration of reactants
Explanation: Doubling the pressure in a liquid phase reaction typically does not alter the concentration of the reactants.
Correct answer: Will not alter the concentration of reactants- A. s-1
- B. mol-1 dm3 s-1
- C. mol-2 dm6 s-1
- D. mol dm-3 s-1
Explanation: In a third-order reaction, the rate law typically involves three concentration terms, such as [A]2[B], leading to a rate constant with…
Correct answer: mol-2 dm6 s-1- A. Option A: Nitrogen gas and hydrogen gas reacting in the presence of solid iron to form ammonia
- B. Option B: Ethylene gas reacting with hydrogen gas in the presence of solid palladium to form ethane
- C. Option C: Sulfur dioxide gas reacting with oxygen gas over a solid vanadium pentoxide catalyst to form sulfur trioxide
- D. Option D: Hydrochloric acid gas reacting with ammonia gas to form ammonium chloride
Explanation: Option D is the correct answer because in this reaction, both the reactants and the catalyst are in the gaseous phase, making it an…
Correct answer: Option D: Hydrochloric acid gas reacting with ammonia gas to form ammonium chloride- A. mol dm-3 sec-1
- B. mol-2 dm6
- C. sec-1
- D. mol-1 dm3 sec-1
Explanation: The rate of a reaction has units of mol dm-3 sec-1. For a second-order reaction, where rate = k[reactant]2, the units of the rate constant…
Correct answer: mol-1 dm3 sec-1- A. Increases
- B. Becomes constant
- C. Decreases
- D. Becomes zero
Explanation: The correct answer is Option D: Becomes zero. A horizontal line on a concentration-time graph indicates that there is no change in…
Correct answer: Becomes zero- A. Molecularity of a reaction is always the same as the order of reaction
- B. In some cases, the molecularity of a reaction is the same as the order of reaction
- C. Molecularity of a reaction is always greater than the order of reaction
- D. All statements above are correct
Explanation: True for elementary reactions, where the rate law can be written directly from the stoichiometry.Example: A→productsA → productsA→products…
Correct answer: In some cases, the molecularity of a reaction is the same as the order of reaction- A. Reactants and activated complex
- B. Reactants and the products
- C. Products and the activated complex
- D. Reactants
Explanation: The activation energy is the minimum energy required to initiate a chemical reaction, appearing as a potential energy hill between the…
Correct answer: Reactants and the products- A. Decrease in activation energy of reaction
- B. Decrease in the number of collisions between molecules of reactants
- C. Increase in activation energy of molecules of reactants
- D. Increase in number of effective collisions
Explanation: As temperature increases, the kinetic energy of molecules also increases.
Correct answer: Increase in number of effective collisions- A. Young needs to be encouraged and supported in society.
- B. A young need to be encouraged and supported in society.
- C. The young needs to be encouraged and supported in society.
- D. The young need to be encouraged and supported in society.
Explanation: The correct choice is D because it is grammatically correct and conveys the intended meaning.
Correct answer: The young need to be encouraged and supported in society.- A. A catalyst changes the potential energies of the reactants and products
- B. A catalyst decreases the temperature of the reaction which leads to a faster rate
- C. A catalyst lowers the activation energy barrier for the reaction by providing a different reaction mechanism.
- D. A catalyst raises the activation energy for the reaction which produces a faster rate
Explanation: Catalysts function by providing an alternate reaction mechanism that has a lower activation energy.Note that a catalyst decreases the…
Correct answer: A catalyst lowers the activation energy barrier for the reaction by providing a different reaction mechanism.531. The minimum amount of energy required by the colliding particles for effective collisions is called:
- A. Activation energy
- B. Lattice energy
- C. Bond energy
- D. Hydration energy
Explanation: Explanation for this question will be added soon.
Correct answer: Activation energy- A. More Energy
- B. No energy
- C. Less Energy
- D. A catalyst
Explanation: Exothermic reactions are bond-making reactions in which heat energy is released.
Correct answer: Less Energy- A. Increasing the activation energy
- B. Decreasing the activation energy
- C. Increasing effective collisions
- D. Combining with reactant molecules
Explanation: The explanation for this question will be added soon.
Correct answer: Combining with reactant molecules- A. Temperature
- B. Concentration
- C. Pressure
- D. Rate constant
- E. All of the above
Explanation: The rate of reaction depends on the concentration of reactants, temperature, pressure (in case of gaseous reactants), and catalyst.
Correct answer: All of the above- A. Concentration of reactants does not affect the rate of a reaction
- B. Surface area of reactants affects rate of reaction
- C. Concentration affects rate of reaction
- D. Catalyst affects rate of a reaction
Explanation: The rate constant which is the proportionality constant that relates the rate of reaction with the concentrations of the reactants is not…
Correct answer: Concentration of reactants does not affect the rate of a reaction- A. Temperature
- B. Pressure
- C. Concentration
- D. Catalyst
Explanation: Explanation for this question will be added soon.
Correct answer: Catalyst- A. Double
- B. Three times
- C. Four times
- D. Five times
Explanation: Explanation for this question will be added soon.
Correct answer: Double- A. First
- B. Second
- C. Third
- D. Zero
Explanation: For a second-order reaction, the half-life is inversely proportional to the initial concentration of the reactant, Hence the correct…
Correct answer: Second- A. 10 s
- B. 20 s
- C. 40 s
- D. 400 s
Explanation: b) 20 s:This option suggests that the half-life of the reaction would remain the same at 20 s when the initial pressure of A is increased…
Correct answer: 20 s- A. Second order reaction
- B. Zero order reaction
- C. Pseudo - unimolecular reaction
- D. First order reaction
Explanation: A pseudo-unimolecular reaction or pseudo first order reaction s a reaction whose rate depends on the concentration of a single reactant…
Correct answer: Pseudo - unimolecular reaction