Chemical Kinetics NCERT Based MCQ Questions for NEET

This article contains NCERT based 45 MCQ questions test on Chemistry chapter "Chemical Kinetics". These questions are highly valuable for the NEET exam. You can attempt these questions in the form of an interactive quiz and calculate your score. Read the below quiz rules carefully before you start

General Instructions

• Quiz contains 45 questions of 4 marks each.
• Correct answer (✔) will award you +4 marks and Incorrect answer (✘) will give you -1 mark.
• Total test is of 180 marks.
• Tap on box in order to select any option that you think is correct.
• Press the Submit button given in the end of quiz to calculate your score.
• There is a PDF file attached in the end of quiz. You can see detailed solutions to all questions and do self analysis from that file as well.

Question 1. For a reactions A + B → Product, it was found that rate of reaction increases four times if concentration of ‘A’ is doubled, but the rate of reaction remains unaffected, if concentration of ‘B’ is doubled. Hence, the rate law for the reaction is

(1) rate = k [A] [B]

(2) rate = k [A]²

(3) rate = k [A]²[B]¹

(4) rate = k [A]²[B]²

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Question 2. The unit of rate constant for a zero order reaction is

(1) litre sec^–1

(2) litre mole^–1 sec^–1

(3) mole litre^–1 sec^–1

(4) mole sec^–1

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Question 3. A first order reaction which is 30% complete in 30 minutes has a half-life period of –

(1) 24.2 min

(2) 58.2 min

(3) 102.2 min

(4) 120.2 min

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Question 4. The order of a reaction which has the rate expression dc/dt = K[E]^3/2 [D]^3/2 is

(1) 3/2

(2) 3

(3) 2

(4) 0

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Question 5. An example of a pseudo-unimolecular reaction is

(1) Dissociation of hydrogen iodide

(2) Hydrolysis of methyl acetate in dilute solution

(3) Dissociation of phosphorus pentachloride

(4) Decomposition of hydrogen peroxide

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Question 6. Which equation is correct for first order reactions

(1) t_1/2 ∝ C^-1

(2) t_1/2 ∝ C

(3) t_1/2 ∝ C⁰

(4) t_1/2 ∝ C^1/2

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Question 7. According to the collision theory of chemical reactions

(1) A chemical reaction occurs with every molecular collision.

(2) Rate is directly proportional to the number of collisions per second.

(3) Reactions in the gas phase are always of zero order.

(4) Reaction rates are of the order of molecular speeds.

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Question 8. The activation energy for a reaction is 9.0 Kcal/mol. The increase in the rate constant when its temperature is increased from 298K to 308K is

(1) 63%

(2) 50%

(3) 100%

(4) 10%

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Question 9. What will be the respective order of reaction and rate constant for a chemical change having t_50% vs concentration (a) curve as –

(1) 0, 1/2

(2) 1, 1

(3) 0, 1

(4) 2, 1

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Question 10. In a reaction, X → Products, when start is made from 8.0 × 10^–2 M of X, half life is

found to be 120 minute. For the initial concentration 4.0 × 10^–2 M, the half life of the reaction becomes 240 minute. The order of the reaction is –

(1) 0

(2) 1

(3) 2

(4) 0.5

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Question 11. For a given reaction the rate of reaction can be represented by

(1)

(2)

(3)

(4) None of these

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Question 12. In the reaction N₂O₅ → 4NO₂ + O₂, initial pressure is 500 atm and rate constant K is 3.38 × 10^-5 sec^-1. After 10 minutes the final pressure of N₂O₅ is

(1) 490 atm

(2) 250 atm

(3) 480 atm

(4) 420 atm

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Question 13. The reaction 2NO (g) + O₂ (g) → 2 NO₂ (g) is of first order. If volume of reaction vessel is reduced to 1/3, the rate of reaction would be –

(1) 1/3 times

(2) 2/3 times

(3) 3 times

(4) 6 times

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Question 14. Decay constant of a reaction is 1.1 × 10^–9 sec^–1, then the half-life of the reaction is

(1) 1.2 × 10⁸

(2) 6.3 × 10⁸

(3) 3.3 × 10⁸

(4) 2.1 × 10⁸

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Question 15. For the reaction

taking place on water, the order of reaction is

(1) 1

(2) 2

(3) 3

(4) 0

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Question 16. The unit of rate constant of first & second order reaction is respectively -

(1) time^–1, mole^–1. litre . time^–1

(2) mole ltr^–1, time^–1

(3) mole^–1. litre. time^–1, time^–1

(4) sec^–1, litre^–1

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Question 17. Consider following two reactions

A → Product → -d[A]/dt = k₁[A]^o

B → Product → -d[B]/dt = k₂[B]

Units of k₁ and k₂ are expressed in terms of molarity (mol L^–1) and time (sec^–1) as –

(1) sec^–1, M sec^–1 (2) M sec^–1,M sec^–1

(3) sec^–1, M^–1 sec^–1 (4) M sec^–1, sec^–1

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Question 18. H₂ gas is adsorbed on the metal surface like tungsten. This follows ______ order reaction

(1) Third

(2) Second

(3) Zero

(4) First

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Question 19. For the reaction system:

2NO(g) + O₂(g) → 2NO₂(g) volume is suddenly reduced to half its value by increasing the pressure on it. If the reaction is of first order with respect to O₂ and second order with respect to NO, the rate of reaction will –

(1) Increase to eight times of its initial value.

(2) Increase to four times of its initial value.

(3) Decrease to one-fourth of its initial value.

(4) Decrease to one-eighth of its initial value.

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Question 20. The rate equation for the reaction 2 A + B → C is found to be : rate = k [A] [B] . The correct statement in relation to this reaction is that the

(1) unit of k must be s^–1.

(2) t_1/2 is a constant.

(3) rate of formation of C is twice the rate of disappearance of A.

(4) value of k is independent of the initial concentrations of A and B.

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Question 21. Consider an endothermic reaction X → Y with the activation energies Eb and Ef for the backward and forward reactions, respectively. In general

(1) E_b > E_f

(2) E_b < E_f

(3) there is no definite relation b/t E_b & E_f

(4) E_b = E_f

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Question 22. Rate of reaction can be expressed by Arrhenius equation as k = Ae^–E/RT, In this equation, E represents –

(1) the energy below which colliding molecules will not react.

(2) the total energy of the reacting molecule at a temperature, T.

(3) the fraction of molecules with energy greater than the activation energy of the reaction.

(4) the energy above which all the colliding molecules will react.

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Question 23. The following mechanism has been proposed for the reaction of NO with Br₂ to form NOBr:

NO(g) + Br₂ (g) → NOBr₂ (g)

NOBr₂ (g) + NO (g) → 2 NOBr (g)

If the second step is the rate determining step, the order of the reaction with respect to NO (g) is -

(1) 0

(2) 3

(3) 2

(4) 1

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Question 24. The time for half-life period of a certain reaction: A→products is 1 hr. When the initial concentration of the reactant ‘A’ is 2.0 mol L^–1, how much time does it take for its concentration to come from 0.50 to 0.25 mol L^–1 if it is a zero-order reaction?

(1) 4 h

(2) 0.5 h

(3) 0.25 h

(4) 1 h

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Question 25. Consider the reaction:

Cl₂(aq) + H₂S(aq) → S(s) + 2 H⁺(aq) + 2 Cl^–(aq)

The rate equation for this reaction is rate = k [Cl₂] [H₂S]

Which of these mechanisms is/are consistent with this rate equation?

(A) Cl₂ + H₂S → H⁺ + Cl^– + Cl⁺ + HS^– (slow)

Cl⁺ + HS^– → H⁺ + Cl^– + S (fast)

(B) H₂S → H⁺ + HS^– (fast equilibrium)

Cl₂ + HS^– → 2Cl^– + H⁺ + S (slow)

(1) B only

(2) Both A and B

(3) Neither A nor B

(4) A only

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Question 26. Under what conditions a bimolecular reaction may be kinetically of first order?

(1) When both reactants have same concentration.

(2) When one of the reacting species is in excess.

(3) When the reaction is at equilibrium.

(4) When the activation energy of reaction is less.

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Question 27. If ‘I’ is the intensity of absorbed light and ‘C’ is the concentration of AB for the

photochemical process AB + hv → AB*, rate of formation of AB* is directly proportional to

(1) C

(2) I

(3) I2

(4) C.I.

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Question 28. In a first order reaction the conc. of reactant decreases from 800 mol/dm3 to 50 mol/dm³ in 2 × 10⁴ sec. The rate constant of reaction in sec^–1 is –

(1) 2 × 10⁴

(2) 3.45 × 10^–5

(3) 1.386 × 10^–4

(4) 2 × 10^–4

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Question 29. Which one of the following statements for order of reaction is not correct?

(1) Order can be determined experimentally.

(2) Order of reaction is equal to sum of the powers of concentration terms in differential rate law.

(3) It is not affected with the stoichiometric coefficient of the reactants.

(4) Order cannot be fractional.

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Question 30. Under the same reaction conditions, initial concentration of 1.386 mol dm^–3 of a substance becomes half in 40 seconds and 20 seconds through first order and zero order kinetics, respectively. Ratio (k₁/k₀) of the rate constants for first order (k₁) and zero order (k₀) of the reactions is –

(1) 0.5 mol^-1 dm³

(2) 1.0 mol dm^-3

(3) 1.5 mol dm^-3

(4) 2.0 mol^-1 dm³

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Question 31. For a first order reaction A → P, the temperature (T) dependent rate constant (k) was found to follow the equation log k = – (2000) 1/T + 6.0

The pre-exponential factor A and the activation energy Ea, respectively, are :

(1) 1.0 × 10⁶ s^–1 and 9.2 kJ mol^–1

(2) 6.0 s^–1 and 16.6 kJ mol^–1

(3) 1.0 × 10⁶ s^–1 and 16.6 kJ mol^–1

(4) 1.0 ×10⁶ s^–1 and 38.3 kJ mol^–1

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Question 32. The concentration of R in the reaction R → P was measured as a function of time and the following data is obtained:

t (min)	0.0	0.05	0.12	0.18
[R] (molar)	1.0	0.75	0.40	0.10

The order of the reaction is –

(1) 0

(2) 3

(3) 2

(4) 1

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Question 33. For the elementary reaction M → N, the rate of disappearance of M increases by a factor of 8 upon doubling the concentration of M. The order of the reaction with respect to M is –

(1) 4

(2) 3

(3) 2

(4) 1

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Question 34. In a reaction 2 HI → H₂ + I₂, the concentration of HI decreases from 0.5 mol

L^–1 to 0.4 mol L^–1 in 10 minutes. What is the rate of reaction during this interval?

(1) 5 × 10^–3 M min^–1

(2) 2.5 × 10^–3 M min^–1

(3) 5 × 10^–2 M min^–1

(4) 2.5 × 10^–2 M min^–1

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Question 35. For a certain reaction a large fraction of molecules has energy more than the threshold

energy, still the rate of reaction is very slow. The possible reason for this could be that

(1) Colliding molecules could be large in size.

(2) The colliding molecules must not be properly oriented for effective collisions.

(3) The rate of reaction could be independent of the energy.

(4) One of the reactants could be in excess.

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Question 36. A plot of log (a – x) against time t is a straight line. This indicates that the reaction is of

(1) Zero order

(2) First order

(3) Second order

(4) Third order

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Question 37. Which of the following statements is not correct for the catalyst?

(1) It catalyzes the forward and backward reaction to the same extent.

(2) It alters ΔG of the reaction.

(3) It is a substance that does not change the equilibrium constant of a reaction.

(4) It provides an alternate mechanism by reducing activation energy between reactants and products.

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Question 38. Consider the reaction: 

2N₂O₄ → 4NO₂.

If and then

(1) 2k’ = k

(2) k’ = 2k

(3) k’ = k

(4) k = ½ k

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Question 39. In the presence of a catalyst, the heat evolved or absorbed during the reaction –

(1) Increases

(2) Decreases4

(3) Remains unchanged

(4) May increase or decrease

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Question 40. Which of the following statements is not correct?

(1) For a zero-order reaction, t_1/2 is proportional to initial concentration

(2) The relationship of variation of rate constant with temperature is given by

(3) The unit of rate constant for a reaction is

mol^1–n L^n–1 s^–1 where n is order of the

reaction.

(4) The unit of rate of reaction changes with

order of reaction.

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Question 41. Consider a first order gas phase decomposition reaction:

A(g) → B(g) + C(g)

The initial pressure of the system before decomposition of A was p_i. After lapse of time ‘t’, total pressure of the system increased by x units and become ‘p_t’. The rate constant k for the reaction is given as _____

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Question 42. For a first order reaction 

A → B; the reaction rate at reactant concentration of 0.01M is found to be 2.0 × 10^–5 mol L^–1 S^–1. The half-life period of the reaction is –

(1) 30s

(2) 220s

(3) 300s

(4) 347s

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Question 43. The rate of reaction between two reactants A and B decreases by a factor of 4 if the concentration of reactant B is doubled. The order of this reaction with respect to reactant B is –

(1) 2

(2) – 2

(3) 1

(4) – 1

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Question 44. For the reaction 2A + B → 3C + D, which of

the following does not express the reaction

rate

(1) −d[B]/dt

(2) d[D]/dt

(3) −½ d[A]/dt

(4) −⅓ d[C]/dt

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Question 45. Consider the reaction:

N₂(g) + 3H₂(g) → 2NH₃ (g).

The equality relationship between d[NH₃]/dt and –d[H]₂/dt is –

(1)

(2)

(3)

(4)

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Detailed Solutions

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