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 2 of 29
- A. Bond energy
- B. Activation energy
- C. Average energy
- D. Enthalpy
Explanation: Activation energy is the barrier reactant molecules must climb to reach the transition state, and only collisions carrying at least this…
Correct answer: Activation energy- A. -d[B]/dt
- B. d[D]/dt
- C. -1/2 d[A]/dt
- D. -1/3 d[C]/dt
Explanation: Rate is expressed as the change in concentration divided by the coefficient, with a minus sign for reactants because they are being…
Correct answer: -1/3 d[C]/dt- A. Rate law
- B. Rate constant
- C. Reaction rate
- D. Reaction order
Explanation: The rate law, or rate equation, states the rate as the rate constant multiplied by concentration terms raised to their experimentally…
Correct answer: Rate law- A. Ea
- B. P.E
- C. V
- D. K.E
Explanation: Activation energy, Ea, is the minimum energy required for reactants to reach the transition state or activated complex.
Correct answer: Ea- A. Pressure
- B. Effective collision
- C. Ineffective collisions
- D. Temperature
Explanation: An activated complex forms when reactant particles undergo an effective collision with suitable energy and orientation, allowing them to…
Correct answer: Effective collision- A. Increases the rate of forward reaction only
- B. Increases the rate of reverse reaction
- C. Increases the rate of forward but decreases the rate of backward reaction
- D. Increases the rate of forward as well as backward reaction equally
Explanation: A catalyst provides an alternative pathway with lower activation energy for both the forward and reverse reactions.
Correct answer: Increases the rate of forward as well as backward reaction equally27. Anything which increases rate of reaction without being involved in the reaction________________?
- A. Promoter
- B. Catalyst
- C. Inhibitor
- D. All of the above
Explanation: A catalyst increases reaction rate by providing an alternative pathway with lower activation energy and is regenerated by the end of the…
Correct answer: Catalyst- A. auto catalysis
- B. Self catalysis
- C. inhibition
- D. Enzyme catalysis
Explanation: Negative catalysis decreases the rate of a reaction and is therefore called inhibition.
Correct answer: inhibition- A. Self catalytic reaction
- B. Enzyme catalytic reaction
- C. Autocatalytic reaction
- D. induced catalysis
Explanation: Nitroglycerine decomposition produces acidic substances that promote further decomposition, so the reaction accelerates through one of its…
Correct answer: Autocatalytic reaction- A. Products
- B. Chemical equilibrium
- C. Reactants
- D. both A & B Chemistry
Explanation: A catalyst changes the rates of the forward and reverse reactions but does not change the final equilibrium composition or the nature of…
Correct answer: both A & B Chemistry- A. Specificity
- B. Special structure
- C. Its own Ea
- D. all of above
Explanation: A catalyst has a particular structure and active surface, so it is selective or specific toward certain reactions, and it provides its own…
Correct answer: all of above- A. The activation energy of the reaction increases
- B. Concentration of the reacting molecules increases
- C. Collision frequency increases
- D. None of these
Explanation: Heating gives reacting molecules more kinetic energy, so they collide more frequently and a greater fraction of collisions has enough…
Correct answer: Collision frequency increases- A. Double decomposition reaction
- B. Neutralization reaction
- C. Ionic reactions
- D. all of above
Explanation: Ionic reactions in aqueous solution are usually very rapid because oppositely charged ions react directly without breaking strong covalent…
Correct answer: all of above- A. Zero
- B. One
- C. Two
- D. Three
Explanation: In R = K[A][B], the powers of the concentration terms are 1 and 1, so the overall order is 1 + 1 = 2.
Correct answer: Two- A. Refractometric method
- B. Dilatometric method
- C. Optical activity method
- D. Half life method
Explanation: The half-life method determines reaction order because the dependence of half-life on initial concentration differs for zero-, first-, and…
Correct answer: Half life method- A. First order
- B. Second order
- C. Third order
- D. Zero order
Explanation: For a second-order reaction with initial concentration a, the half-life is t1/2 = 1/(k a), so the stated inverse relationship with k and…
Correct answer: Second order- A. Order of reaction
- B. Molecularity
- C. Rate of reaction
- D. Average of reaction
Explanation: In a rate law such as rate = k[A]^m[B]^n, the sum of the exponents m + n is the overall order of the reaction.
Correct answer: Order of reaction- A. Single
- B. Square
- C. Cube
- D. Raise to power four
Explanation: For a single-reactant third-order reaction, the half-life varies inversely with the square of the initial reactant concentration, written…
Correct answer: Square- A. All electrolytes
- B. Strong electrolytes
- C. Non electrolytes
- D. Weak electrolytes
Explanation: Ostwald's dilution law relates the degree of ionisation of a weak electrolyte to its concentration and is derived using its equilibrium…
Correct answer: Weak electrolytes- A. Arrhenius constant
- B. Molecularity
- C. Specific rate constant
- D. Ideal rate constant
Explanation: The specific rate constant, or rate constant k, is the reaction rate when the molar concentrations of all reactants in the rate expression…
Correct answer: Specific rate constant