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 7 of 29
- A. Dry cell
- B. Nickel Cadmium battery
- C. Magnesium cell
- D. None of these
Explanation: Solar panels typically store energy in rechargeable batterics such as Nickel Cadmium (NiCo) batteries, Lithium-ion batteries, or lead acid…
Correct answer: Nickel Cadmium battery- A. 44.5 days
- B. 1.3 million years
- C. 3.8 days
- D. 2.5 billion years
Explanation: The isotope of tron with mass number 59 (59 F'e) has a half-life of approximately 44.5 days.
Correct answer: 44.5 days- A. 15000
- B. 25000
- C. 50000
- D. None of these
Explanation: The half-life of the element is 5 days. After each half-life, the number of atoms is reduced by half* Initial amount: 50,000 atoms* After…
Correct answer: None of these- A. Rejuvenation
- B. Revoking
- C. Recycling
- D. None of these
Explanation: The process of bringing an element in use after its complete half-life is known as Rejuvenation
Correct answer: Rejuvenation- A. Increases the rate of reaction
- B. Decreases the rate of reaction
- C. Keeps the rate constant
- D. None of these
Explanation: The effect of a catalyst in a chemical reaction is to increase the rate of the reaction.
Correct answer: Increases the rate of reaction- A. Concentration of reactants collectively is unity
- B. Concentration of each of the reactants is unity
- C. Either a or b
- D. None of these
Explanation: When the concentration of all the reactants collectively is unity, the rate of reaction is equal to the specific rate constant.
Correct answer: Concentration of reactants collectively is unity- A. Negative catalysis
- B. Heterogeneous catalysis
- C. Activation of catalyst
- D. Autocatalysis
Explanation: If product formed act as a catalyst is called autocatalyst and reaction is called auto catalysis.One of the simplest examples of this is…
Correct answer: Autocatalysis- A. Concentration of reactants decreases
- B. The order of reaction changes
- C. Concentration of product decreases
- D. Temperature of the system changes
Explanation: According to law of mass action, rate of reaction is directly proportional to product of active masses of reactant.
Correct answer: Concentration of reactants decreases- A. Fast
- B. Moderate
- C. Slow
- D. Very slow
Explanation: If energy of activated complex is close to energy of reactant, then reaction is fast, and spontaneous.
Correct answer: Fast- A. Heat of reaction
- B. Rate of reaction
- C. Has no effect on the reaction
- D. Energy of activation
Explanation: The minimum energy required for an effective collision in a bimolecular gas-phase reaction is called the energy of activation.
Correct answer: Energy of activation- A. Lower the activation energy
- B. Increase the activation energy
- C. Lower the pH
- D. Decrease
Explanation: A positive catalyst increases rate of reaction, decreases activation energy, decreases equilibrium time and changes mechanism of reaction.
Correct answer: Lower the activation energy- A. Urease
- B. Zymase
- C. Invertase
- D. Sucrase
Explanation: Zymase is an enzyme complex generally formed in yeast. It catalyzes the conversion of glucose to form ethanol and carbon dioxide.
Correct answer: Zymase- A. 1 min
- B. 0.693 min
- C. 2 min
- D. 4 min
Explanation: It can be calculated using the following formula: t½ = (0.693 / k) Given that the rate constant (k) is 0.693 min⁻¹, you can calculate the…
Correct answer: 1 min- A. Concentration of one reactant
- B. Concentration of two reactants
- C. Concentration of three reactants
- D. Independence of the initial concentration
Explanation: In a first-order reaction, the rate depends on the concentration of one reactant.
Correct answer: Concentration of one reactant- A. 24 minutes
- B. 120 minutes
- C. 72 minutes
- D. 48 minutes
Explanation: First, find out how many half-lives it takes to reach 25% (which is 1/4) of the original concentration:- (¼) = 2 , where 'n' is the number…
Correct answer: 48 minutes- A. Very fast reaction
- B. Very slow reaction
- C. Moderately reactive
- D. Not predicted
Explanation: Conversely, if the iron used in the reaction is not pure and contains substances that inhibit or interfere with the reaction, it could…
Correct answer: Very slow reaction- A. Neutralization of acids and bases
- B. Explosive reaction of O2 and H2
- C. Organic substitution reaction
- D. Photochemical reactions
Explanation: Slow reactions are those that take a noticeable amount of time to complete.Neutralization of acids and bases and organic substitution…
Correct answer: Organic substitution reaction- A. The vessel must remain open
- B. Reacting molecules should have less energy than Ea at time of collision
- C. Reacting molecules must be properly oriented and energy more than or equal to Ea
- D. The reacting molecules must not collide with each other
Explanation: In addition to having sufficient energy, reacting molecules must collide with the correct orientation.Proper orientation ensures that the…
Correct answer: Reacting molecules must be properly oriented and energy more than or equal to Ea- A. 512
- B. 614
- C. 400
- D. 112
Explanation: Rate roughly doubles every 10K. Temperature rises from 10K → 100K → 9 steps of 10K. So, rate increase = 2 =512.
Correct answer: 512- A. Decreases
- B. Increases
- C. Remains constant
- D. Not predicted
Explanation: According to collision theory, increasing the concentration of reactants increases the number of collisions per unit time, which increases…
Correct answer: Increases