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 22 of 29
- A. Zero
- B. Two
- C. One
- D. Half
Explanation: Concentration of A is quadrupled So, ratio of [A1] : [A2] = 4 Rate of reaction doubles So, ratio of rate of reaction 1 : rate of reaction…
Correct answer: Half- A. 1
- B. 3
- C. 2
- D. 0
Explanation: If the concentration is doubled then the ratio is= 2 Rate quadruples when concentration doubles, so the ratio of rate = 4 Order of…
Correct answer: 2- A. 0.693/k
- B. log 2/k
- C. 0.693/2k
- D. In2/k
Explanation: Rate equation for the above reaction is Rate = k[N2O5] Since it is a first order reaction, ∴ t1/2 ∝ 1 / k (where t1/2 is half life and k…
Correct answer: 0.693/k- A. 2.5
- B. 15
- C. 30
- D. 35
Explanation: The specific rate constant is the rate of reaction when the concentration of each of the reactants is unity.
Correct answer: 30- A. Condition
- B. Mechanism
- C. Concentration
- D. Parameters
Explanation: The order of reaction provides valuable information about the mechanism of reaction.
Correct answer: Mechanism- A. 1
- B. 3
- C. 2
- D. 0
Explanation: The rate constant of a reaction has the same units as the rate of reaction when the order of the reaction is zero.
Correct answer: 0- A. Reactants
- B. Reactants and the products
- C. Products
- D. Products and Activated complex
Explanation: The activation energy appears as a potential energy hill between reactants and the products for carrying out the reaction.
Correct answer: Reactants and the products- A. Ef > Er
- B. Ef < Er
- C. Ef >>> Er
- D. Ef = Er
Explanation: The answer is Ef < Er. An exothermic reaction is a reaction that releases heat.
Correct answer: Ef < Er- A. Optical rotation
- B. Dilatometric
- C. Refractrometric
- D. Electrical conductivity
Explanation: The answer is electrical conductivity. Electrical conductivity is the ability of a substance to conduct electricity.
Correct answer: Electrical conductivity- A. 10 kcal mol-1
- B. 15 kcal mol-1
- C. 20 kcal mol-1
- D. Zero
Explanation: The activation energy for the reverse reaction B → A is 10 kcal mol^-1.
Correct answer: 10 kcal mol-1431. If the energy of the activated complex lies close to energy of reactants, it means that reaction is
- A. Slow
- B. Endothermic
- C. Exothermic
- D. Exothermic and fast
Explanation: The activated complex is the highest-energy state of a reaction. If the energy of the activated complex is close to the energy of the…
Correct answer: Exothermic and fast- A. Very fast and increasing
- B. Slow and decreasing
- C. Moderate and decreasing
- D. Continuously increasing
Explanation: The speed of the rate-determining step is slow. The rate-determining step is the slowest step in a reaction mechanism.
Correct answer: Slow and decreasing- A. Decreases products
- B. Increases products
- C. Affects negligibly
- D. Improves reaction efficiency
Explanation: The effect of a decrease in reactants concentration on protium concentration increases the product concentration.
Correct answer: Increases products- A. mol dm3 sec-1
- B. mol dm3 minute-1
- C. mol dm-3 sec-1
- D. mol dm3 hour-1
Explanation: The correct answer is mol dm-3 sec-1. The rate of reaction is the change in concentration of a reactant or product over time.
Correct answer: mol dm-3 sec-1- A. Volume
- B. Pressure
- C. Density
- D. Temperature
Explanation: Molar concentration is the number of moles of a substance per unit volume.
Correct answer: Pressure- A. Average rate
- B. Instantaneous rate
- C. Reaction rate
- D. None of the above
Explanation: The rate of a chemical reaction at any one instant during the reaction is called the "instantaneous rate", therefore option B is correct.
Correct answer: Instantaneous rate- A. Higher
- B. Equal to
- C. Lower
- D. Comparable
Explanation: At the start of the chemical reaction, the instantaneous rate is higher than the average rate, therefore option A is correct.
Correct answer: Higher- A. Rate of reaction and concentration of reacting substance
- B. Rate of reaction and concentration of products
- C. Concentration of reactants and concentration of products
- D. Concentration of reactants and catalysts
Explanation: Option A is correct because the law of mass action expresses the relationship between the rate of a chemical reaction and the…
Correct answer: Rate of reaction and concentration of reacting substance- A. Refractive Index
- B. Optical activity
- C. Concentration
- D. Density
Explanation: The optical rotation method is concerned with the study of the chiral or optically active properties of reacting substances, therefore…
Correct answer: Optical activity- A. First order
- B. Third order
- C. Second order
- D. Pseudo-first order
Explanation: If the reactant acting as the solvent is present in a vast excess compared to other reactants, the reaction can be approximated as a…
Correct answer: Pseudo-first order