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 13 of 29
- A. Excess
- B. Limiting
- C. Extent
- D. None of the above
Explanation: The limiting reagent (or limiting reactant) in a chemical reaction is the substance which is totally consumed when the chemical reaction…
Correct answer: Limiting- A. 3.23 x 10^-21J
- B. 4.11 x 10^-21J
- C. 6.21 x 10^-21J
- D. 7.71 x 10^-21J
- E. 9.11 x 10^-21J
Explanation: =(3/2) x 1.38 x 10-23x (27=273)=6.21 x 10-21 JSo the correct option is C.
Correct answer: 6.21 x 10^-21J- A. Reversible process
- B. Irreversible process
- C. Efficient process
- D. Entropic process
Explanation: A reversible process can be retraced in reverse order, without producing any change in the surrounding.
Correct answer: Irreversible process- A. s-1
- B. moles dm-3 s-1
- C. moles dm-3
- D. mol-1 dm3
Explanation: Unit of K = (Unit of Rate) / (Unit of [A]) Unit of K = (mol/L/s) / (mol/L) Unit of K = 1/s Therefore, the unit of the rate constant (K)…
Correct answer: s-1- A. Completed instantaneously
- B. Slow
- C. Economical
- D. None of these options are correct
Explanation: The rate of reaction is defined as the change in concentration of a reactant or a product divided by the time taken for the change.Rate of…
Correct answer: Economical- A. Conditions of temperature
- B. Initial concentration of the compound
- C. Presence of catalyst
- D. All of these
Explanation: For a first-order reaction, the half-life is a constant that is determined by the rate constant and does not depend on the initial…
Correct answer: Initial concentration of the compound- A. Straight line
- B. Parabola
- C. Curve
- D. Scattered graph
Explanation: Drawing a graph between concentration change with time typically gives a representation of the rate of a chemical reaction.
Correct answer: Curve- A. 3.23 x 10^-21 J
- B. 4.11 x 10^-21 J
- C. 6.21 x 10^-21 J
- D. 7.71 x 10^-21 J
- E. 9.11 x 10^-21 J
Explanation: The average translational kinetic energy of molecules in a gas is given by the formula: K.E. = (3/2) kTWhere K.E.
Correct answer: 6.21 x 10^-21 J- A. Reversible process
- B. Irreversible process
- C. Efficient process
- D. Entropic process
Explanation: An irreversible process can be defined as a process in which the system and the surroundings do not return to their original condition…
Correct answer: Irreversible process- A. One
- B. Two
- C. Three
- D. Zero
Explanation: The units of Kc are as follows;For Zero order reaction → moldm^-3sec^-1For 1st order reaction → sec^-1For 2nd order reaction →…
Correct answer: One- A. 1M
- B. 2M
- C. 3M
- D. 4M
Explanation: The rate constant "R" in a rate equation represents the rate of reaction when the concentration of each reactant is 1M (molar).
Correct answer: 1M- A. Instantaneous rate of reaction
- B. Average rate of reaction
- C. Rate of reaction
- D. Minimum rate of reaction
Explanation: The average rate of reaction is calculated by taking the ratio of the change in concentration of reactants or products over a specific…
Correct answer: Average rate of reaction- A. Constant
- B. Equilibrium
- C. Greater
- D. Lesser
Explanation: The correct option is C, greater. If the slope of the curve is greater near the start of the reaction, it indicates a rapid initial…
Correct answer: Greater- A. Decomposition of nitrogen dioxide
- B. Decomposition of hydrogen iodide
- C. Gas phase oxidation of nitric oxide
- D. Formation of hydrogen iodide
Explanation: Option C is correct as gas phase oxidation of nitric oxide is a third order reaction.
Correct answer: Gas phase oxidation of nitric oxide255. As compared to exothermic-reaction, formation of activated complex in endothermic reaction requires:
- A. Greater Ea
- B. Smaller Ea
- C. Equal Ea
- D. No Ea
Explanation: The correct option is A as the endothermic reactions have a greater activation energy because the products of this reaction have more…
Correct answer: Greater Ea- A. Zero order
- B. First order
- C. Second order
- D. Third order
Explanation: IThe rate equation rate = k[A][B] indicates that the reaction rate depends on the concentrations of two reactants, A and B.
Correct answer: Second order- A. Electrical conductivity method
- B. Optical rotation method
- C. Refractometric method
- D. Spectrometry
Explanation: Electrical conductivity method - Correct. Since ions conduct electricity, changes in conductivity can help monitor the reaction rate
Correct answer: Electrical conductivity method- A. Zero
- B. First
- C. Second
- D. Third
Explanation: Second: Correct. The second-order half-life matches the given expression.
Correct answer: Second- A. Catalyst reacts with reactant
- B. Catalysts reacts with product
- C. Energy of activation decreases
- D. Energy of activation increases
- E. Energy of activation
Explanation: Reaction rate increases by adding catalyst because it decreases activation energy, so Option C is the correct answer.
Correct answer: Energy of activation decreases- A. Pressure
- B. Surface area
- C. Volume
- D. Surface tension
- E. Temperature
Explanation: The correct answer is option B is the Surface area.In the case of pulverized CaCu3 (calcium carbide), the increased surface area provides…
Correct answer: Surface area