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 9 of 29
- A. 2, 1, 3
- B. 1, 2, 3
- C. 0, 1, 2
- D. 2, 1, 0
Explanation: The rate law expression is = K [A]1 [B]2 The order of the reaction with respect to A and B s 1 and 2 respectively.
Correct answer: 1, 2, 3- A. Henderson's equation
- B. General gas equation
- C. Arrhenius equation
- D. Van der Waals equation
Explanation: In physical chemistry, the 'Arrhenius equation' is a formula for the temperature dependence of reaction rates- k= Ae(-Ea/RT) where A=…
Correct answer: Arrhenius equation163. If energy of the activated complex is close to energy of reactants, it means that the reaction is:
- A. Fast
- B. Moderate
- C. Slow
- D. Very slow
Explanation: Activated complex is formed once the activation energy is reached by the reactants.
Correct answer: Fast164. As the concentration of reactant increases, the rate of reaction also increases, it is because:
- A. K.E. increases in molecules
- B. Oscillation increases between molecules
- C. Collisions frequency increases
- D. Temperature of molecules increases
Explanation: Collisions frequency increases: The frequency of collisions between reactant particles is the number of collisions that occur per unit…
Correct answer: Collisions frequency increases- A. 3 x 10^-3 Ms-1
- B. 3 x 10^-4 Ms-1
- C. 3 x 10^-6 Ms-1
- D. 3 x 10^-7 Ms-1
Explanation: Rate constant of the first order reaction (K) = 3 x 10-6 per sec and initial concentration [A] = 0.10 M.
Correct answer: 3 x 10^-7 Ms-1- A. Stops the reaction.
- B. Decreases the rate of reaction.
- C. Alters the rate of reaction.
- D. Increases the rate of reaction.
Explanation: A catalyst is a substance that increases the rate of a chemical reaction without itself undergoing any permanent chemical change.
Correct answer: Increases the rate of reaction.167. 75% of a first order reaction is completed in 36 minutes. What is the half life of the reaction?
- A. 27 min
- B. 24 min
- C. 18 min
- D. 42 min
Explanation: Completion of 75% of reaction = 25% left From 100% conc of reactants to 25% 2 half lives have elapsed.
Correct answer: 18 min- A. 0
- B. 1
- C. 2
- D. 3
Explanation: The order of a chemical reaction is defined as the sum of the powers of the concentration of the reactants in the rate equation of that…
Correct answer: 3- A. The temperature of the reaction
- B. The concentration of reactants.
- C. Concentration of products
- D. Catalyst used
Explanation: Zero order reactions are those in which the concentration of the reactants does not change over time and the concentration rates remain…
Correct answer: The concentration of reactants.- A. 1
- B. 3
- C. 2
- D. 0
Explanation: The correct answer is (d) 0. In photochemical reactions, the rate is independent of the concentrations of the reactants (zeroth order) and…
Correct answer: 0- A. Rate constant
- B. Enthalpy
- C. Temperature
- D. Rate of a reaction
Explanation: Yes, the type of reactants or product decides the nature of the method adapted for finding enthalpy.Enthalpy is a measure of the heat…
Correct answer: Enthalpy- A. At Equilibrium
- B. One Instant
- C. Given Temperature
- D. Given Pressure
Explanation: The instantaneous rate is the rate of a reaction at any particular point in time, a period of time that is so short that the…
Correct answer: One Instant- A. Time Constant
- B. relative rate constant
- C. Instantaneous rate constant
- D. velocity constant
Explanation: specific rate constant is the propotionality constant in the equation that expresses the relationship between the rate of a chemical…
Correct answer: velocity constant- A. Rate = k [POCl3][H2O]3
- B. Rate = k [PCl5][H2O]
- C. Rate = k [PCl5][H2O]4
- D. Rate = [PCl5][H2O]
Explanation: For the rate equation, the reactants of ONLY the rate-determining step, which is the slow step, are taken into account in a multi-step…
Correct answer: Rate = k [PCl5][H2O]- A. Concentration of the reactants becomes irrelevant
- B. Reaction proceeds without any transition state
- C. Number of efficient or fruitful collisions increase
- D. Molecules of the reactants move slowly
Explanation: Option A is incorrect because the concentration of reactants, still, is a factor regardless of other factors such as low activation…
Correct answer: Number of efficient or fruitful collisions increase- A. Co-factor
- B. Iso-zyme
- C. Active site
- D. Substrate
Explanation: The 'substrate' is the reactant in a chemical reaction when acted upon by an enzyme.
Correct answer: Substrate177. The number of reacting molecules which change their concentration in a chemical change is called:
- A. Extent of a Reaction
- B. Order of a Reaction
- C. Specific rate of a reaction
- D. Enthalpy of reaction
Explanation: The 'order of a chemical reaction' can be defined as the sum of the power of concentration of reactants in the rate law expression is…
Correct answer: Order of a Reaction- A. Second Order
- B. Zero Order
- C. First Order
- D. Third Order
Explanation: A second-order reaction is a type of chemical reaction that depends on the concentrations of a one second-order reactant or two…
Correct answer: Second Order- A. k
- B. kv
- C. kf
- D. ks
Explanation: The rate constant in chemical reactions is indeed denoted by the symbol "k".
Correct answer: k- A. Number of reactant molecule
- B. Number of moles of reactant
- C. Number of moles of product
- D. Order of Reactions
Explanation: This equation is derived based on the rate constant α and the order of reaction n. Hence, option D is correct.
Correct answer: Order of Reactions