1. Select the rate law that corresponds to the data shown for the following reaction:
2. For an exothermic reaction, the energy of activation of the reactants is
(a) equal to the energy of activation of products
(b) less than the energy of activation of products
(c) greater than the energy of activation of products
(d) Sometimes greater and sometimes less than that of the products
3. A chemical reaction is catalyzed by a catalyst X. Hence X
(a) reduces enthalpy of the reaction
(b) decreases rate constant of the reaction
(c) increases activation energy of the reaction
(d) does not affect equilibrium constant of the reaction
4. A substance ‘A’ decomposes by a first order reaction starting initially with [A] = 2.00 m and after 200 min, [A] becomes 0.15 m. For this reaction t1/2is
(a) 53.72 min
(b) 50.49 min
(c) 48.45 min
(d) 46.45 min
5. The rate of reaction depends upon the
(a) volume
(b) force
(c) pressure
(d) conc. of reactants
6. In a reversible reaction the energy of activation of the forward reaction is 50 kcal. The energy of activation for the reverse reaction will be
(a) < 50 kcal
b) either greater than or less than 50 kcal
(c) 50 kcal
(d) > 50 kcal
7. The plot of concentration of the reactant vs. time for a reaction is a straight line with a negative slope. The reaction follows a
(a) zero order rate equation
(b) first order rate equation
(c) second order rate equation
(d) third order rate equation
8. 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
9. Half life of a first order reaction is 4 s and the initial concentration of the reactants is 0.12 M. The concentration of the reactant left after 16 s is
(a) 0.0075 M
(b) 0.06 M
(c) 0.03 M
(d) 0.015 M
10. In the following reaction, how is the rate of appearance of the underlined product related to the rate of disappearance of the underlined reactant?
11. When a biochemical reaction is carried out in laboratory in the absence of enzyme then rate of reaction obtained is 10–6 times, then activation energy of reaction in the presence of enzyme is
(a) 6/RT
(b) Different from Ea obtained in laboratory
(c) Pis required
(d) Can’t say anything
12. For the reaction 2N2O5 →4NO2+O2 , rate and rate constant are 1.02×10-4 mollit-1 sec-1
and 3.4×10-5sec-1 respectively then concentration of N2O5 at that time will be
(a) 1.732M
(b) 3M
(c) 3.4 × 105M
(d) 1.02 × 10–4M
13. In the reaction 3A⟶2B, rate of reaction
14. 3 A → B + C it would be a zero order reaction , when (a) the rate of reaction is proportional to square of concentration of A
(b) the rate of reaction remains same at any concentration of A
(c) the rate remains unchanged at any concentration of Band C
(d) the rate of reaction doubles if concentration of Bis increased to double
15. The temperature dependence of rate constant (k) of a chemical reaction is written in
16. If the rate of the reaction is equal to the rate
constant, the order of the reaction is
(a) 3
(b) 0
(c) 1
(d) 2
17. The activation energy for a simple chemical reaction, A→B is Ea in forward direction. The activation energy for the reverse reaction:
(a) Is always double of Ea
(b) Is negative of Ea
(c) Is always less than Ea
(d) Can be less than or more than Ea
18. The reaction A
The time taken for 0.8 mole if A to produce 0.6 mole of B is 1 hour. What is the time taken for conversion of 01.9 mole of A to produce 0.675 mole of B ?
(a) 2 hours
(b) 1 hour
(c) 0.5 hour
(d) 0.25 hour
19. The rate of a first order reaction is 1.5 × 10-2 mol L-1min-1at 0.5 Mconcentration of the reactant. The half life of the reaction is
(a) 0.383 min
(b) 23.1 min
(c) 8.73 min
(d) 7.53 min
20 For a first order reaction A à B he reaction rate at reactant concentration of 0.01 M is found to be 2.0 X 10-5 mol L-1 S-1.The hjalf life period of the reaction is
(a) 30 s
(b) 220 s
(c) 300 s
(d) 347 s
21. 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:
(a) 2
(b) 2
(c) 1
(d) 1
26. If 60% of a first order reaction was completed in 60 minutes, 50% of the same reaction would be completed in approximately (log 4 = 0.60, log 5 = 0.69)
(a) 45 minutes
(b) 60 minutes
(c) 40 minutes
(d) 50 minutes
30. Half life period of a first-order reaction is 1386 seconds. The specific rate constant of the reaction is:
(a) 0.5 × 10-2s-1
(b) 0.5 × 10-2s-1
(c) 5.0 × 10-2s-1
(d) 5.0 × 10-2s-1
31. For the reaction A + B → products, it is observed that
(a) on doubling the initial concentration of A only, the rate of reaction is also doubled and
(ii) on doubling the initial concentration of both A and B, there is a change by a factor of 8 in the rate of the reaction.
The rate of this reaction is given (a) rate = k [A] [B]2
(b) rate = k [A]2[B]2
(c) rate = k [A] [B]
(d) rate = k [A]2[B]
32. For the reaction N2O5(g) → 2NO2(g) + (1/2)O2(g) the value of rate of disappearance of N2O5 is given as 6.25 x 10-3 mol L-1 s-1. The rate of formation of NO2 and O2 is given respectively (a) 6.25 × 10-3mol L-1s-1and 6.25 × 10-3mol L-1s-1
(b) 1.25 × 10-2mol L-1 s-1 and 3.125 × 10-3molL-1s-1
(c) 6.25 × 10-3mol L-1s-1and 3.125 × 10-3molL-1s-1
(d) 1.25 × 10-2mol L-1s-1and 6.25 × 10-3mol L-1s-1
33.For an endothermic reaction, energy of activation is Ea and enthalpy of reaction is ΔH (both of these in kj/mol). Minimum value of Ea will be
(a) less than DH
(b) equal to DH
(c) more than DH
(d) equal to zero
35. Which one of the following statements for the order of a reaction is incorrect?
(a) Order can be determined only experimentally.
(b) Order is not influenced by stoichiometric coefficient of the reactants.
(c) Order of reaction is sum of power to the concentration terms of reactants to express the rate of reaction.
(d) Order of reaction is always whole number.
37. The unit of rate constant for a zero order reaction is
(a) mol L-1s-1
(b) L mol L-1s-1
(c) L2mol L-1s-1
(d) s-1
38.In a reaction, A +B à Product, rate is doubled when the concentration of B is doubled, and rate increased by a factor of 8 when the concentration of both the reactants (A and B) are doubled rate , law for the reaction can be written as :
(a) Rate = k[A][B]2
(b) Rate = k[A]2[B]2
(c) Rate = k[A] [B]
(d) Rate = k[A]2B]
39. In a zero-order reaction for every 10° rise of temperature, the rate is doubled. If the temperature is increased from 10°C to 100°C, the rate of the reaction will become:
(a) 256 times
(b) 512 times
(c) 64 times
(d) 128 times
41. What is the activation energy for a reaction if its rate doubles when the temperature is raised from 20°C to 35°C? (R= 8.314 Jmol-1K-1)
(a) 269 kJmol-1
(b) 34.7 kJmol-1
(c) 15.1 kJmol-1
(d) 342 kJmol-1
42. A reaction having equal energies of activation for forward and reverse reaction has:
(a) D G = 0
(b) D H = 0
(c) D H = D G = D s = 0
(d) D S = 0
43. A reaction is 50% completed in 2 hours and 75% completed in 4 hours. The order of reaction is
(a) 0
(b) 1
(c) 2
(d) 3
44. For a reaction between Aand B the order with respect to Ais 2 and the order with respect to B is 3. The concentrations of both Aand Bare doubled, the rate will increase by a factor of:
(a) 10
(b) 12
(c) 16
(d) 32
45. For the reaction of 4A + B → 2C + D. Which of the following statement is not correct ?
(a) The rate of formation of C and D are equal
(b) The rate of formation of D is one half the rate of consumption of A
(c) The rate of appearance of C is one half the rate of disappearance of B
(d) The rate of disappearance of B is one fourth of the rate of disappearance of A
46. T50 of first -order reaction is 10 min. Starting with 10 mol L–1, rate after 20 min is
(a) 0.0693 × 5 mol L–2 min–1
(b) 0.0693 × 10 mol L–1 min–1
(c) 0.0693 mol L–1 min–1
(d) 0.0693 × 2.5 mol L–1 min–1
47. The rate of first-order reaction is 0.04 mol L-1 s-1 at 10 seconds and 0.03 mol L-1 s-1 at 20 seconds after initiation of the reaction. The half-life period of the reaction is
(a) 44.1 s
(b) 54.1 s
(c) 24.1 s
(d) 34.1 s
48. The rate constant of a reaction changes when …
(a) pressure is changed
(b) concentration of reactants changed
(c) a catalyst is added
(d) temperature is changed
49. The rate constant of the reaction A → B is 0.6 x 10-3 mol L-1 s-1. If the concentration of A is 5 M, then concentration of B after 20 minutes is
(a) 3.60 M
(b) 1.08 M
(c) 0.36 M
(d) 0.72 M
50. The rate constant for the reaction,
2N2O5 →4NO2 +O2 is 3.0×10-4 s-1. If start made with 1.0 mol L–1 of N2O5, calculate the rate of formation of NO2 at the moment of the reaction when concentration of O2 is 0.1 mol L–1.
(a) 2.7×10-4 molL-1 s-1
(b) 2.4×10-4 molL-1 s-1
(c) 4.8×10-4 molL-1 s-1
(d) 9.6×10-4 molL-1 s-1
52. A reaction involving two different reactants can never be
(a) unimolecular reaction
(b) first order reaction
(c) second order reaction
(d) bimolecular reaction
54. Collision theory is used to explain how chemical species undergo a reaction. Using this theory and the kinetic molecular model, which of the following does NOT influence the rate of a chemical reaction?
(a) The temperature of the system
(b) The geometry or orientation of the collision
(c) The velocity of the reactants at the point of collision
(d) All of the above influence the rate
56. NO2(g) + CO(g) → NO(g) + CO2(g), the rate law is: Rate = k [NO2]2 . If 0.1 mole of gaseous carbon monoxide is added at constant temperature to the reaction mixture
which of the following statements is true?
(a) Both k and the reaction rate remain the same
(d) Only k increases, the reaction rate remain the same
(c) Both k and the reaction rate increase
(d) Both k and the reaction rate decrease
57. For the reaction A + B → products, it is observed that
(a) on doubling the initial concentration of A only, the rate of reaction is also doubled and
(ii) on doubling the initial concentration of both A and B, there is a change by a factor of 8 in the rate of the reaction. The rate of this reaction is given by
(a) rate = k[A][B]2
(b) rate = k[A][B]
(c) rate = k[A]2[B]2
(d) rate = k[A]2[B]
58. The reactions of higher order are rare because
(a) many bady collisions involve very high activation energy
(b) many bady collisions can take place only in the gaseous phase
(c) many bady collisions have a low probability
(d) many bady collisions are not energetically favoured
59. The rate constants k1, and k2 for two different reactions are 1016.e-2000/T and 1015.e-1000/T, respectively. The temperature at which k1 = k2 is
(a) 2000 K
(b) 2000/2.303 K
(c) 1000/2.303 K
(d) 1000 K
61. A reaction which is of first order w.r.t. reactant A, has a rate constant 6 min–1. If we start with [A] = 0.5 mol L–1, when would [A] reach the value of 0.05 mol L–1
(a) 0.384 min
(b) 0.15 min
(c) 3 min
(d) 3.84 min
63. The activation energy for a simple chemical reaction A ⇋ B is Ea in forward direction. The activation energy for reverse reaction
(a) is negative of Ea
(b) is always double of Ea
(c) is always less than Ea
(d) can be less than or more than Ea
64. When a biochemical reaction is carried out in laboratory, outside the human body in absence of enzyme, then rate of reaction obtained is 10-6 times, the activation energy of reaction in the presence of enzyme is
(a) 6/RT
(b) P is required
(c) different from Ea obtained in laboratory
(d) can’t say anything.
65. Mechanism of a hypothetical reaction
X2 + Y2 → 2XY is given below :
(i) X2 → X + X(fast)
(ii) X + Y2 XY + Y (slow)
(iii) X + Y → XY (fast)
The overall order of the reaction will be :
(1) 2
(2) 0
(3) 1.5
(4) 1
66. A first order reaction has a specific reaction rate of 10-2 sec-1 . How much time will it take for 20g of the reactant to reduce to 5 g ?
(1) 138.6 sec
(2) 346.5 sec
(3) 693.0 sec
(4) 238.6 sec
67. The compound C7H8 undergoes the following reactions:RM
69. If the rate constant for a first order reaction is k, the time (t) required for the completion of 99% of the reaction is given by:
(a) t = 0.693/k
(b) t = 6.909/k
(c) t =4.606 /k
(d) t =2.303/k
71. The rate constant for a first order reaction is 4.606 × 10–3 s–1. The time required to reduce 2.0 g of the reactant to 0.2 g is :
(1) 500 s
(2) 1000 s
(3) 100 s
(4) 200 s
72. An increase in the concentration of the reactants of a reaction leads to change in
(1) threshold energy
(2) collision frequency
(3) activation energy
(4) heat of reaction
73. For a reaction A B, enthalpy of reaction is –4.2 kJ mol-1 and enthalpy of activation is 9.6 kJ mol-1 . The correct potential energy profile for the reaction is shown in option.
75. The slope of Arrhenius plot of first order reaction is –5 × 103K. The value of Ea of the reaction is. Choose the correct option for your answer.
[Given R = 8.314 JK-1 mol-1 ]
(1) –83 kJ mol-1
(2) 41.5 kJ mol-1
(3) 83.0 kJ mol-1
(4) 166 kJ mol-1
Solutions :
