Class 12 Chemistry MCQ Chapter 3 Chemical Kinetics
Are you searching for AHSEC Class 12 Chemistry MCQ Chapter 3 Chemical Kinetics English Medium? If yes, then you are in the right place. This article provides a complete collection of Multiple Choice Questions (MCQs) with accurate answers and detailed explanations from Chapter 3 Chemical Kinetics for AHSEC Higher Secondary students.
These MCQ solutions are prepared according to the latest AHSEC syllabus and examination pattern. The questions cover all important topics of Chemical Kinetics, including rate of reaction, factors affecting reaction rate, rate law, rate constant, order of reaction, molecularity, integrated rate equations, half-life, and activation energy. Regular practice of these objective questions will help students develop a strong understanding of the chapter and improve their performance in examinations.
All questions and answers are written in simple and easy-to-understand English, making them suitable for quick revision and effective exam preparation. Whether you are preparing for unit tests, school examinations, competitive exams, or the AHSEC Higher Secondary Final Examination 2027, these MCQ solutions will help you strengthen your concepts and score higher marks.
Practice these Chapter 3 Chemical Kinetics MCQs regularly to improve accuracy, speed, and confidence before your examinations.
Chemical Kinetics
Part I
VSA & MCQ
I. Short Question-Answer
Q. What is chemical kinetics?
Ans: It is the study of rates of chemical reactions and factors affecting them.
Q. What is rate of reaction?
Ans: Change in concentration of reactant or product per unit time.
Q. Write rate expression.
Ans: Rate = −d[R]/dt or d[P]/dt
Q. What is the average rate?
Ans: Change in concentration over a finite time interval.
Q. What is an instantaneous rate?
Ans: Rate at a particular instant of time.
Q. What is a rate law?
Ans: Relation between rate and concentration of reactants.
Q. What is the rate constant (k)?
Ans: Proportionality constant in rate law.
Q. What is the order of reaction?
Ans: Sum of powers of concentration terms in rate law.
Q. What is molecularity?
Ans: Number of molecules colliding in an elementary step.
Q. What is a zero-order reaction?
Ans: Reaction whose rate is independent of concentration.
Q. Write rate law for zero order reaction.
Ans: Rate = k
Q. What is first order reaction?
Ans: Reaction whose rate depends on first power of concentration.
Q. Write rate law for first order reaction.
Ans: Rate = k[A]
Q. What is second order reaction?
Ans: Reaction whose rate depends on square of concentration or product of two concentrations.
Q. What is half-life (t1/2)?
Ans: Time required for concentration to become half.
Q. Expression for half-life of first order reaction.
Ans: t1/2 = 0.693/k
Q. What is activation energy?
Ans: Minimum energy required for reaction to occur.
Q. What is Arrhenius equation?
Ans: k = A e^(−Ea/RT)
Q. What is collision theory?
Ans: Reactions occur due to effective collisions.
Q. What is catalyst?
Ans: Substance that changes rate without being consumed.
Q. What is positive catalyst?
Ans: Increases rate of reaction.
Q. What is negative catalyst?
Ans: Decreases rate of reaction.
Q. What is enzyme?
Ans: Biological catalyst.
Q. What is pseudo-first order reaction?
Ans: Reaction that appears first order due to excess of one reactant.
Q. What is integrated rate law?
Ans: Expression showing concentration as function of time.
Q. Unit of rate constant for first order reaction.
Ans: s⁻¹
Q. Unit of rate constant for second order reaction.
Ans: L mol⁻¹ s⁻¹
Q. What is threshold energy?
Ans: Minimum energy for effective collision.
Q. What is frequency factor (A)?
Ans: Number of collisions per unit time.
Q. Rate of reaction depends on:
(a) Concentration
(b) Temperature
(c) Catalyst
(d) All
Ans: (d)
Q. Unit of rate is:
(a) mol L⁻¹ s⁻¹
(b) mol L⁻¹
(c) s⁻¹
(d) mol
Ans: (a)
Q. Zero order rate is:
(a) k
(b) k[A]
(c) k[A]²
(d) 1/k
Ans: (a)
Q. First order rate constant unit:
(a) s⁻¹
(b) mol L⁻¹
(c) L mol⁻¹
(d) s
Ans: (a)
Q. Half-life of first order depends on:
(a) Initial concentration
(b) k
(c) Temperature
(d) Pressure
Ans: (b)
Q. Activation energy is:
(a) Maximum energy
(b) Minimum energy
(c) Average energy
(d) Zero energy
Ans: (b)
Q. Catalyst changes:
(a) ΔH
(b) Rate
(c) Equilibrium
(d) Energy levels
Ans: (b)
Q. Increasing temperature:
(a) Decreases rate
(b) Increases rate
(c) No change
(d) Stops reaction
Ans: (b)
Q. Arrhenius equation relates:
(a) Rate and pressure
(b) k and temperature
(c) k and volume
(d) Rate and volume
Ans: (b)
Q. Molecularity is defined for:
(a) Overall reaction
(b) Elementary step
(c) Catalyst
(d) Product
Ans: (b)
Q. Second order unit of k:
(a) s⁻¹
(b) L mol⁻¹ s⁻¹
(c) mol L⁻¹
(d) L
Ans: (b)
Q. Enzymes are:
(a) Inorganic
(b) Biological catalysts
(c) Metals
(d) Salts
Ans: (b)
Q. Pseudo-first order occurs when:
(a) Both reactants equal
(b) One reactant excess
(c) No reactant
(d) Low temperature
Ans: (b)
Q. Assertion: Rate increases with temperature.
Reason: More molecules have higher energy.
(a) Both true, R correct explanation
(b) Both true, R not correct explanation
(c) A true, R false
(d) A false, R true
Ans: (b)
Q. Assertion: Catalyst increases rate.
Reason: Lowers activation energy.
(a) Both true, R correct explanation
(b) Both true, R not correct explanation
(c) A true, R false
(d) A false, R true
Ans: (d)
Q. Assertion: First order half-life is constant.
Reason: Independent of concentration.
(a) Both true, R correct explanation
(b) Both true, R not correct explanation
(c) A true, R false
(d) A false, R true
Ans: (c)
Q. Assertion: Molecularity cannot be zero.
Reason: At least one molecule participates.
(a) Both true, R correct explanation
(b) Both true, R not correct explanation
(c) A true, R false
(d) A false, R true
Ans: (a)
Q. Assertion: Rate law is determined experimentally.
Reason: Cannot be predicted from equation.
(a) Both true, R correct explanation
(b) Both true, R not correct explanation
(c) A true, R false
(d) A false, R true
Ans: (b)
Q. Assertion: Zero order rate is constant.
Reason: Independent of concentration.
(a) Both true, R correct explanation
(b) Both true, R not correct explanation
(c) A true, R false
(d) A false, R true
Ans: (d)
Q. Assertion: Activation energy affects rate.
Reason: Higher Ea lowers rate.
(a) Both true, R correct explanation
(b) Both true, R not correct explanation
(c) A true, R false
(d) A false, R true
Ans: (c)
