MCQs for Chemistry Class 12 with Answers Chapter 4 Chemical Kinetics
Students of class 12 Chemistry should refer to MCQ Questions Class 12 Chemistry Chemical Kinetics with answers provided here which is an important chapter in Class 12 Chemistry NCERT textbook. These MCQ for Class 12 Chemistry with Answers have been prepared based on the latest CBSE and NCERT syllabus and examination guidelines for Class 12 Chemistry. The following MCQs can help you to practice and get better marks in the upcoming class 12 Chemistry examination
Chapter 4 Chemical Kinetics MCQ with Answers Class 12 Chemistry
MCQ Questions Class 12 Chemistry Chemical Kinetics provided below have been prepared by expert teachers of grade 12. These objective questions with solutions are expected to come in the upcoming Standard 12 examinations. Learn the below provided MCQ questions to get better marks in examinations.
Question. In a slow reaction, rate of reaction generally ………. with time:
(c) sometimes increases and sometimes decreases.
(d) remains constant
Question. The rate of a chemical reaction tells us about,
(a) the reactants taking part in reaction
(b) the products formed in the reaction
(c) how slow or fast the reaction is taking place
(d) None of the above
Question. At the beginning the decrease in the conc. of reactants is
(d) None of above
Question. In the reaction 2A BA2B, if the concentration of A is doubled and that of B is halved, then the rate of the reaction will:
(a) increase 2 times
(b) increase 4 times
(c) decrease 2 times
(d) remain the same
Question. Rate law cannot be determined from balanced chemical equation if _________.
(a) reverse reaction is involved
(b) it is an elementary reaction
(c) it is a sequence of elementary reactions
(d) any of the reactants is in excess
Question. In the reaction, A B, the rate of reaction increases two times on increasing the concentration of A four times, the order of reaction is
Question. Consider figure and mark the correct option.
(a) Activation energy of forward reaction is E1 + E2 and product is less stable than reactant.
(b) Activation energy of forward reaction is E1 + E2 and product is more stable than reactant.
(c) Activation energy of both forward and backward reaction is E1 + E2 and reactant is more stable than product.
(d) Activation energy of backward reaction is E1 and product is more stable than reactant.
Question. The role of a catalyst is to change ________________.
(a) gibbs energy of reaction
(b) enthalpy of reaction
(c) activation energy of reaction
(d) equilibrium constant
Question. In a reaction, when the concentration of reactant is increased two times, the increase in rate of reaction was four times. Order of reaction is :
Question. The rate constant of a first order reaction is 6.9103s1 . How much time will it take to reduce the initial concentration to its 1/8th value?
(a) 100 s
(b) 200 s
(c) 300 s
(d) 400 s
Question. Which of the following is a zero order reaction?
(a) Decomposition of N2O5
(b) Decomposition of NH3
(c) Decomposition of N2O
(d) Radioactive decay of unstable nuclei
Question. Diazonium salt decomposes as C6H5N2Cl C6H5Cl + N2 at 0° C. The evolution of N2 becomes two times faster when the initial concentration of the salt is doubled. Therefore it is
(a) a first order reaction
(b) a second order reaction
(c) independent of the initial concentration of the salt
(d) a zero order reaction
Question. Which of the following reaction does not occur fastly ?
(a) Precipitation of AgCl by mixing aqueous solutions of AgNO3 and NaCl.
(b) Burning of gasoline
(c) Rusting of iron
(d) Burning of LPG for cooking
Question. Chemical kinetics is a study to find out
(a) the feasibility of a chemical reaction
(b) extent to which a reaction will proceed
(c) speed of a reaction
(d) All of the above
Question. Instantaneous rate of a chemical reaction is
(a) rate of reaction in the beginning
(b) rate of reaction at the end
(c) rate of reaction at a given instant
(d) rate of reaction between two specific time intervals
Question. In the graph plotted between ln [R] and t for a first order reaction, the intercept on y-axis is
(a) – k
(c) ln [R]0
Question. The activation energy of a reaction is zero. The rate of the reaction
(a) increases with increase of temperature
(b) decreases with decrease of temperature
(c) decreases with increase of temperature
(d) is nearly independent of temperature
Question. The activation energy of a reaction can be determined from the slope of which of the following graphs?
(a) ln k vs 1/T
(b) T/ln k vs 1/T
(c) ln k vs T
(d) lnk/T vs T
Question. A reaction proceeds by first order, 75% of this reaction was completed in 32 min. The time required for 50% completion is
(a) 8 min
(b) 16 min
(c) 20 min
(d) 24 min
Question. Point out the wrong statement: or a first order reaction
(a) time for half-change (t1/2) is independent of initial concentration
(b) change in the concentration unit does not change the rate constant (k)
(c) time for half-change × rate constant = 0.693
(d) the unit of k is mole–1 min–1
Question. The value of rate constant of a pseudo first order reaction _________.
(a) depends on the concentration of reactants present in small amount.
(b) depends on the concentration of reactants present in excess.
(c) is independent on the concentration of reactants.
(d) depends only on temperature.
Question. In the presence of a catalyst, the heat evolved or absorbed during the reaction ________________.
(c) remains unchanged
(d) may increase or decrease
Question. Rate of a reaction can be defined as
(a) the rate of decrease in concentration of any one of the reactants
(b) the rate of increase in concentration of any one of the products
(c) the rate of decrease in concentration of any one of the reactants or the rate of increase in concentration of any one of the products
(d) the sum of rate of decrease in concentration of all the reactants or the rate of increase in concentration of all the products
Question. The rate of reaction
(a) increases as the reaction proceeds
(b) decreases as the reaction proceeds
(c) remains the same as the reaction proceeds
(d) may decrease or increase as the reaction proceeds
Question. The rate constant of reaction is 2.0 × 10–6 mol–2 L2 s–1. The order of the reaction is
Question. Which of the following statements are applicable to a balanced chemical equation of an elementary reaction?
(a) Order is same as molecularity.
(b) Order is less than the molecularity.
(c) Order is greater than the molecularity.
(d) Molecularity can never be zero.
Question. The unit of rate constant of a zero order reaction is
(a) litre second–1
(b) litre mole–1 second–1
(c) mole litre–1 second–1
(d) mole second–1
Question. In a reaction, the threshold energy is equal to
(a) activation energy + normal energy of reactants
(b) activation energy – normal energy of reactants
(c) normal energy of reactants – activation energy
(d) average kinetic energy of molecules of reactants
Question. The rate of reaction between two specific time intervals is called
(a) instantaneous rate
(b) average rate
(c) specific rate
(d) ordinary rate
Question. In a first order reaction, reactant concentration C varies with time t as
(a) 1 / C increases linearly with t
(b) log C decreases linearly with t
(c) C decreases with 1 / t
(d) log C decreases with 1 / t
Question. In the reaction, 2N2O5 → 4NO2 + O2 , initial pressure is 500 atm and rate constant k is 3.38 x 10-5 s-1 . After 10 min the final pressure of N2O5 is
(a) 490 atm
(b) 250 atm
(c) 480 atm
(d) 420 atm
Question. If the rate of reaction A ➔ B doubles on increasing the concentration of A by 4 times, the order of the reaction is
(c) 1/ 2
Question. Mathematical expression for t1/4 i.e. when (1/4)th reaction is over following first order kinetics can be given by
(a) t1/4 = 2.303/k log 4
(b) t1/4 = 2.303/k log 2
(c) t1/4 = 2.303/k log 4/3
(d) t1/4 = 2.303/k log 3/4
Question. Consider the following two reactions,
A → Product – d[A]/dt = k1 [AJ0
B → Product – d[B]/dt = k2 [B]1
k1 and k2 are expressed in terms of molarity (mol L-1 )and time (s-1) as
(a) s-1 ,Ms-1 L- 1
(b) Ms-1 ,Ms-1
(c) s-1 ,M-1 s-1
(d) Ms-1 ,s-1
Question. A catalyst increases rate of reaction by
(a) decreasing enthalpy
(b) decreasing internal energy
(c) decreasing activation energy
(d) increasing activation energy
Question. Rate of which reaction increases with temperature :
(a) of any type of reactions
(b) of exothemic reactions
(c) of endothemic reactions
(d) of none
Question. Activation energy of the reaction is
(a) the energy released during the reaction
(b) the energy evolved when activated complex is formed
(c) minimum amount of energy needed to overcome the potential barrier
(d) the energy needed to form one mole of the product
Question. The order of a reaction, with respect to one of the reacting component Y, is zero. It implies that:
(a) the reaction is going on at a constant rate
(b) the rate of reaction does not vary with temperature
(c) the reaction rate is independent of the concentration of Y
(d) the rate of formation of the activated complex is zero
Question. If the rate of a gaseous reaction is independent of pressure, the order of reaction is:
Question. The rate of a gaseous reaction is given by the expression, rate = k[A] [B]. If the volume of the reaction vessel is suddenly reduced to 1/4 of the initial volume, the reaction rate related to original rate will be
(b) 1/ 8
Question. Which of the following is not correct about order of a reaction?
(a) The order of a reaction can be a fractional number.
(b) Order of a reaction is experimentally determined quantity.
(c) The order of a reaction is always equal to the sum of the stoichiometric coefficients of reactants in the balanced chemical equation for a reaction.
(d) The order of a reaction is the sum of the powers of molar concentration of the reactants in the rate law expression.
Question. If the rate of the reaction is equal to the rate constant, the order of the reaction is
Question. In the Haber process for the manufacture of ammonia the following catalyst is used
(a) Platinized asbestos
(b) Iron with molybdenum as promoter
(c) Copper oxide
Question. Activation energy of a chemical reaction can be determined by
(a) evaluating rate constant at standard temperature
(b) evaluating velocities of reaction at two different temperatures
(c) evaluating rate constants at two different temperatures
(d) changing concentration of reactants
Question. In respect of the equation k AeEa / RT in chemical kinetics, which one of the following statements is correct ?
(a) A is adsorption factor
(b) Ea is energy of activation
(c) R is Rydberg’s constant
(d) k is equilibrium constant
Question. According to the collision theory of reaction rates, the rate of reaction increases with temperature due to
(a) greater number of collision
(b) higher velocity of reacting molecules
(c) greater number of molecules having the activation energy
(d) decrease in the activation energy
Question. Which of the following has been used to explain the subject of chemical kinetics
(a) Collision theory of bimolecular reactions
(b) The activated complex theory
(c) Arrhenius equation
(d) All of these
We hope the above multiple choice questions for Class 12 Chemistry for Chapter 4 Chemical Kinetics provided above with answers based on the latest syllabus and examination guidelines issued by CBSE, NCERT and KVS are really useful for you. Chemical Kinetics is an important chapter in Class 12 as it provides very strong understanding about this topic. Students should go through the answers provided for the MCQs after they have themselves solved the questions. All MCQs have been provided with four options for the students to solve. These questions are really useful for benefit of class 12 students. Please go through these and let us know if you have any feedback in the comments section.