# Class 12 Chemistry Chapter 3 Chemical Kinetics MCQ

### Chemical Kinetics Class 12 MCQ with Answers

Chemical Kinetics Class 12 Chemistry MCQ Question and Answer for the Students of CBSE. All the MCQ’s are Important for Your Exam.

(1) Which factors affects the rate of reaction?

(b) Concentration

(c) Temperature

(c) Pressure

(d) All of the above

Ans : All of the above

(2) The change in concentration of a reactant or product in unit time is called as –

(a) Speed of a reaction

(b) Rate of a reaction

(c) Kinetic energy

(d) Both a and b.

Ans :  Both a and b

(3) Rate of disappearance of R = ?

(a) Δt/ Δp

(b) ΔP/ ΔR

(c) R/t

(d) Δ[R]/ Δt

Ans :Δ[R]/Δt

(4) Rate of appearance of P = ?

(a) – Δ[R]/ Δt

(b) + Δ[P]/ Δt

(c) ΔR/ Δt

(d) – Δ[P]/ Δt

Ans :+ Δ[P]/ Δt

(5) From the concentrations of C4H9Cl at 50s time given, below, calculate the average rate of the reaction in moll-1?

C4HgCl +H₂O → C4HgOH + HCl

(a) 0.100

(b) 0.841

(c) 0.721

(d) 0.0905

Ans : 0.0905

(6) From concentration of C4HgCl at 350S, calculate the instantaneous rate ?

C4HgCl + H₂O C4HgOH + HCL

(a) 1.22 x 10-4 moll-1s-1

(b) 1.0 x 10-4 moll-1s-1

(c) 6.4 × 10-4 moll-1s-1

(d) 4.2 × 10-4 moll-1s-1

Ans : 1.0 × 10-4 moll-1s-1

(7) The decomposition of N2O5 in CCl4 at 318K has been studied by monitoring the concentrations of N₂O5 in the solution. Initially the concentration of N₂O5is 2.33 molL-1 and after 184 minutes it is reduced to 2.08 moll-1, the reaction takes place according to the equation.

2N2O5 (g) 6 + 4NO2 (g)+ O2(g)

Calculate the average rate of this reaction in term of Hours.

(a) 6.79 × 10-4 molL-1/h

(b) 4.07 x 10-2 molL-1/h

(c) 4.32 × 10-4 molL-1/h

(d) 1.13 x 10-2 molL-1/h

Ans : 4.07 x 10-2 molL-1/h

(8) For the reaction R → P, the concentration of a reactant changes from 0.03 m to 0.02M in 25 minutes. Calculate the average rate of reaction using units of time both in minutes and seconds.

(a) 1.471 x 10-19 MS-1

(b) 6.66 x 10-6 MS-1

(c) 4.23 x 10-4 MS-1

(d) 3.29 x 10-5 MS-1

Ans : 6.66 x 10-6MS-1

(9) In the reaction, 2A → Products, the concentration of A decreases from 0.5 molL-1 to 0.4 molL-1 in 10 minutes. calculate the rate during this interval ?

(a) 0.005 molL-1 min-1

(b) 4.502 molL-1 min-1

(c) 3.222 molL-1 min-1

(d) 2.224 molL-1 min-1

Ans : 0.005 molL-1 min-1

(10) The representation of rate of reaction in terms of concentration of the reactants is known as –

(a) Product

(b) Rate constant

(c) Rate law

(d) Rate

Ans : rate law

(11) Rate law is also called as –

(a) Rate equation

(b) Rate expression

(c) Rate constant

(d) Both a and b

Ans : Both a and b

(12) K is also called as –

(a) rate constant

(b) Proportionality constant

(c) rate law

(d) Both a and b

Ans : Both a and b

(13) How much the initial rate of formation of No₂ in molL-1S-1?

[Initial rate [No] = 0.30molL-1;Initial [0₂] = 0.30 molL-1]

(a) 0.389

(b) 0.192.

(c) 0.768

(d) 0.0.96

Ans : 0.096

(14) How much the initial rate of formation of (NO2] in molL-1S-1?

(Initial (NO) = 0.60 molL-1; Initial (O₂] = 0.60 molL-1]

(a) 0.768

(b) 0192

(c) 0.384

(d) 0.096

Ans : 0.768

(15) Calculate the overall order of a reaction which has the rate expression.

[a] Rate = k [A]1/2 [B]3/2

(a) First order

(b) Second order

(c) Half order

(d) Third order

Ans : second order

(16) Calculate the overall order of a reaction which has the rate expression.

[a] Rate = k [A]3/2 [B]-1

(a) First order

(b) Second order

(c) Third order

(d) Half order.

Ans : Half order

(17) The reaction taking place in one step are called-

(a) Complex reaction.

(b) Elementary reaction

(c) Chemical reaction.

(d) Both a and b

Ans:Elementary reaction.

(18) A sequences of elementary reactions gives us the products, the reactions are called

(a) Elementary reaction

(b) Chemical reaction

(c) Complex reaction

(d) Both a and c

Ans : Complex reaction

(19) What is the unit of rate constant of zero order reaction ?

(a) molL-1S-1

(b) mol S-1

(c) S-1

(d) mol-1L S-1

Ans : molL-1S-1

(20) What is the unit of rate constant of first order reaction?

(a) molL-1S

(b) molL S-1

(c) S-1

(d) mol-1L S-1

Ans : S-1

(21) What is the Unit if rate constant of second order reaction?

(a) molL-1S

(b) molL S-1

(c) S-1

(d) mol-1L S-1

Ans :mol-1L S-1

(22) Identify the reaction order from each of the following rakconstant ?

1. k = 2.3 x 10-5 L mol-1s-1

(a) First order

(b) Second order

(c) Half order

(d) Zero order

Ans: Second order

(23) The overall rate of the reaction is controlled by the slowest step in a reaction called as –

(a) Rate determining step

(b) Molecularity

(c) Rate law

(d) Rate constant

Ans : Rate determining step

(24) For the reaction, A + B → Product; the rate law is given by r = k {A}1/2 [B]2. What is the order of the reaction?

(a) 2

(b) 0

(c) 1

(d) 2.5

Ans : 2.5

(25) The conversion of molecules X to Y follows Second order kinetics, if concentration of X is increased to three times how will it affect the rate of formation of Y?

(a) Increase 9 times

(b) Increase 5 times

(c) Decrease 5 times

(d) Decreases 9 times.

Ans : Increase 9 times

(26) The initial concentration of N2O5 in the following first order reaction N2O5 (g) → ½ O2 (g) was 1.24 x 10-2 molL-1 at 318 k the concentration of N2O5 after 60 minutes was 0.20 x 10-2 molL-1. Calculate the rate constant of the reaction at 318 k ?

(a) 0.0304 min-1

(b) 4.2004 min-1

(c) 2.321 min-1

(d) 0.224 min-1

Ans : 0.0304 min-1

(27) A first order reaction has a rate constant 1.15 x 10³s-1. How long will 5g of this reactant take to reduce to 3g

(a) 345 S

(b) 444 S

(c) 367 S

(d) 543 S

Ans : 444 S

(28) Time required to decompose SO₂Cl₂ to half of its initial amount is 60 minutes if the decomposition is a first order reaction. Calculate the rate constant of the reaction?

(a) 1.925 x 10-4 S-1

(b) 4.234 × 10-4 S-1

(c) 3.224 x 10-5 S-1

(d) 2.459 x 10-4 S-1

Ans : 1.925 x 10-4 S-1

(29) A stands for –

(a) Arrhenius factor

(b) Frequency factor

(c) Activation energy

(d) Both a and b

Ans : Both a and b.

(30) R stands for –

(a) Arrhenius factor

(b) Frequency factor

(c) Gas constant

(d) Activation energy

Ans : Gas Constant

(31) Activation energy measured in

(a) J/mol

(b) mol S-1

(c) mol

(d) molL-1 S-1

Ans :J/mol

(32) The energy required to form the intermediate called activated complex is known as –

(a) Frequency Factor

(b) Activation energy

(c) Kinetic energy

(d) Arrhenius factor

Ans : Activation energy

(33) The constants of a reaction at 500 k and 100 k are 0.02 S-1 and 0.07 S-1 respectively. Calculate the values of Ea ?

(a) 18230.8 J

(b) 14240.4 J

(c) 1.2320 J

(d) 184.44 J

Ans : 18230.8 J

(34) The rate constants of a reaction at 500 k and 700 k are 0.02 S-1 and 0.07 S-1 respectively. Calculate A

(a) 2.42

(b) 4.64

(c) 2.32

(d) 1.61

Ans : 1.61

(35)  The first order rate constant for the decomposition of ethyl iodide by the reaction.

C2H5 (g) ->  C2H4 (g) + HI (g)

At 600 k is 1.60 x 10-5 S-1 its energy of activation is 209 KJ/mol calculate the rate constant of reaction at 700k.

(a) 4.723 x 10-5 S-1

(b) 2.224 x 10-6 S-1

(c) 6.36 x 10-3 S-1

(d) 5.234 x 10-4 S-1

Ans : 6.36 x 10-3 S-1

(36) The number of colloisions per second per unit volume of the reaction mixer is known as –

(a) Gibbs energy

(b) Rate law

(c) Rate constant

(d) Collision frequency

Ans : collision frequency

(37) Z represents for –

(a) Colloistion frequency

(b) Effective collision

(c) Rate constant

(d) Gibbs energy

Ans :Colloistion frequency

(38) The rate of the chemical reaction doubles for an increase of 10 k in absolute temperature from 298 k. Calculate Ea

(a) 52.891 KJ mol-1

(b) 42.424 KJ mol-1

(c) 7.894 KJ mol-1

(d) 74.224 KJ mol-1

Ans : 52.891 KJ mol-1

(39) What is Unit of Ea?

(a) KJ mol

(b) KJ

(c) KJ mol-1

(d) J mol-1

Ans :  KJ mol-1

(40) The activation energy for the reaction 2HI → H2 + I2 (g) is 209.5 KJ mol-1 at 581 K, Calculate the fraction of molecules of reactants having energy equal to or greater than activation energy ?

(a) 4.232 x 10-10

(b) 2.232 x 10-14

(c) 1.471 x 10-19

(d) 4.789 x 10-25

Ans : 1.471 x 10-19

(41) Activation energy + energy possessed by reacting species = ?

(a) Effective collisions

(b) Threshold energy

(c) Colloision frequency

(d) Gibbs energy

Ans : Threshold energy

(42) The collisions in which molecules colloide with sufficient kinetic energy and proper orientation. so as to facilitate breaking of bonds between reaching species and formation of new bonds to form products are called as –

(a) Effective collisions

(b) Threshold energy

(c) colloision frequency

(d) Gibbs energy

Ans : Effective Collisions.

Updated: August 25, 2023 — 11:49 pm