Free Order of Reaction MCQs with Answers
33 Order of Reaction 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 order shows how the rate depends on the concentration of each reactant, as expressed in the rate law. Coverage includes zero, first and second-order reactions, integrated rate equations, half-life, units of rate constants and the distinction between overall order and molecularity.
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33 questions · page 1 of 2
- A. is always equal to its coefficient in the balanced equation
- B. is the power to which its concentration is raised in the experimentally determined rate equation
- C. can never be zero
- D. is always a whole number
Explanation: Order is an experimental quantity and must be measured, because the balanced equation describes the overall stoichiometry while the rate…
Correct answer: is the power to which its concentration is raised in the experimentally determined rate equation- A. 1
- B. 2
- C. 3
- D. 4
Explanation: Overall order is the sum of the individual orders, so 1 for A plus 2 for B gives 3.
Correct answer: 3- A. doubles when the concentration doubles
- B. is independent of the concentration of the reactant
- C. falls to zero immediately
- D. is proportional to the square of the concentration
Explanation: A zero order reaction proceeds at a constant rate until the reactant is nearly exhausted, because something other than concentration…
Correct answer: is independent of the concentration of the reactant- A. first order in A
- B. second order in A
- C. third order in A
- D. zero order in A
Explanation: If concentration has no effect on rate then the exponent of that term must be zero, since anything raised to the power zero equals one.
Correct answer: zero order in A- 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. zero order reaction
- B. 1 order reaction
- C. 2 order reaction
- D. 3 order reaction
Explanation: the first order reaction does not dependent on concentration because as only one reactant is involved in rate determining step.The rate…
Correct answer: 1 order reaction- A. Rate=k
- B. Rate = k[A][B]
- C. Rate = k[A]
- D. Rate = k[B]
Explanation: Rate laws or rate equations are mathematical expressions that describe the relationship between the rate of a chemical reaction and the…
Correct answer: Rate = k[A]- A. T½ = k/0.693
- B. T½ = 0.693/k
- C. None of these
- D. T½ = 0.693k
Explanation: The half-life of first-order reactions is given by the equation:T1/2 = 0.693/kwhere 'k' is the rate constant.
Correct answer: T½ = 0.693/k- A. Overall order of reaction
- B. Order of reaction with respect to A
- C. All of these
- D. Order of reaction with respect to B
Explanation: The overall order of the reaction is determined by adding the individual orders which in the given equation are given by 'a' and 'b' where…
Correct answer: Overall order of reaction- A. ax b
- B. a - b
- C. b - a
- D. a + b
Explanation: In any chemical reaction, we can have more than two reactants reacting and giving some products.
Correct answer: a + b- A. Negative order reaction
- B. First order reaction
- C. Zero order reaction
- D. Second order reaction
Explanation: In second-order reactions, the rate of reaction is directly proportional to the square of the concentration of the concerned reactant.
Correct answer: Second order reaction- A. 1
- B. 2
- C. 3
- D. 4
- E. 5
Explanation: The order of a reaction is determined by summing the exponents of the concentration terms in the rate law.
Correct answer: 3- A. First
- B. Second
- C. Third
- D. Zero
Explanation: For a second-order reaction, the half-life is inversely proportional to the initial concentration of the reactant, Hence the correct…
Correct answer: Second- A. 10 s
- B. 20 s
- C. 40 s
- D. 400 s
Explanation: b) 20 s:This option suggests that the half-life of the reaction would remain the same at 20 s when the initial pressure of A is increased…
Correct answer: 20 s- A. Second order reaction
- B. Zero order reaction
- C. Pseudo - unimolecular reaction
- D. First order reaction
Explanation: A pseudo-unimolecular reaction or pseudo first order reaction s a reaction whose rate depends on the concentration of a single reactant…
Correct answer: Pseudo - unimolecular reaction- A. First order reaction
- B. Second order reaction
- C. Third order reaction
- D. Zero order reaction
Explanation: In the zero-order reaction, the rate is independent of the concentration of reactants and hence, the units of rate and rate constant…
Correct answer: Zero order reactionOrder of Reaction MCQs: common questions
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There are 33 Order of Reaction MCQs in the Chemistry bank, shown 20 to a page with the correct answer and an explanation on each.
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