JEE Questions for Chemistry Chemical Kinetics Quiz 7 - MCQExams.com

Which one of the following is wrongly matched ?
  • Saponification of CH3COOC2H5 — second order reaction
  • Hydrolysis of CH3COOCH3 — pseudo unimolecular reaction
  • Decomposition of H2O2 — first order reaction
  • Combination of H2 and Br2 to give HBr — first order reaction
The decomposition of N2 O5 occurs as 2N2 O5 → 4NO2 + O2, and follows 1st order kinetics, hence
  • the reaction is unimolecular
  • the reaction is bimolecular
  • t1/2 ∝ a0
  • None of the above
In the reaction, 2N2O5 → 4NO2 + O2, initial pressure is 500 atm and rate constant k is 3.38 × 10-5 s -1. After 10 min the final pressure of N2O5 is
  • 490 atm
  • 250 atm
  • 480 atm
  • 420 atm
Mathematical expression for t1/4 i.e. when (1/4)th reaction is over following first order kinetics can be given by

  • Chemistry-Chemical Kinetics-1657.png
  • 2)
    Chemistry-Chemical Kinetics-1658.png

  • Chemistry-Chemical Kinetics-1659.png

  • Chemistry-Chemical Kinetics-1660.png
A plot of 1/ T versus k for a reaction gives the slope -1 × 104 K. The energy of activation for the reaction is (Given, R = 8.314 K-1 mol-1 )
  • 83.14 J mol-1
  • 1.202 kJ mol-1
  • 12.02 J mol-1
  • 83.14 kJ mol-1
The rate of reaction doubles when its temperature changes from 300 K to 310 K. Activation energy of such a reaction will be (R = 8.314 JK-1 mo1-1 and log 2 = 0.301)
  • 53.6 kJ mo1-1
  • 48.6 kJ mo1-1
  • 58.5 kJ mo1-1
  • 60.5 kJ mo1-1
N2 (g) + 2H2 (g) ⇌ 2NH3 (g) + 22 kcal
The activation energy for the forward reaction is 50 kcal. What is the activation energy for the backward reaction?
  • 72 kcal
  • 28 kcal
  • -72 kcal
  • -28 kcal
A given sample of milk turns sour at room temperature (27°C) in 5 h. In a refrigerator at -3° C, it can be stored 10 times longer. The energy of activation for the souring of milk is
  • 2.303 × 5 R kJ mol-1
  • 2.303 × 3 R kJ mol-1
  • 2.303 × 2.7 R kJ mol-1
  • 2.303 × 10 R kJ mol-1
The activation energy of a reaction at a given temperature is found to be 2.303 RT J mol- 1 . The ratio of rate constant to the Arrhenius factor is
  • 0.01
  • 0.1
  • 0.02
  • 0.001
The activation energy of exothermic reaction A → B 80 kJ mol-1 . The heat of reaction is 200 kJ mol-1. The activation energy for the reaction B → A (in kJ mol-1 ) will be
  • 80
  • 120
  • 40
  • 280
For a first order reaction A → P, the temperature (T) dependent rate constant (k) was found to follow the equation log k = - (/ T + 6.0
The pre-exponential factor A and the activation energy Ea, respectively, are
  • 1.0 × 106s -1 and 9.2 kJ mo1-1
  • 6.0 s -1 and 16.6 kJ mol-1
  • 1.0 × 106 s -1 and 16.6 kJ mol -1
  • 1.0 × 106 s-1and 38.3 kJ mo1-1
The energies of activation for forward and reverse reactions for A2 + B2 ⇌ 2AB are 180 kJ mol-1 and 200 kJ mol-1 respectively. The presence of a catalyst lowers the activation energy of both (forward and reverse) reactions by 100 kJ mol-1. The enthalpy change of the reaction (A2 + B2 → 2AB)in the presence of catalyst will be (in kJ mol-1)
  • 300
  • 120
  • 280
  • 20
Rate of a reaction can be expressed by Arrhenius equation as k = Ae-E/RT In this equation, E represents
  • the energy above which all the colliding molecules will react
  • the energy below which colliding molecules will not react
  • the total energy of the reacting molecules at a temperature, T
  • the fraction of molecules with energy greater than the activation energy of the reaction
The rate constant of a first order reaction at 27°C is 10-3 min -1. The temperature coefficient of this reaction is 2. What is the rate constant (in min -1) at 17°C for this reaction ?
  • 10-3
  • 5 × 10-4
  • 2 × 10-3
  • 10-2
Arrhenius equation is
  • ∆H = ∆E + ∆ng RT
  • ∆G = ∆H —T • ∆S
  • k = Ae-Ea / RT
  • None of these
Consider an endothermic reaction X →Y with the activation energies Eb and Ef for the backward and forward reactions respectively. In general
  • there is no definite relation between Eb and Ef
  • Eb = Ef
  • Eb > Ef
  • Eb < Ef
The rate law for the reaction RCl + NaOH → ROH + NaCl(aq ) is given by, Rate = k [RCl]. The rate of the reaction will be
  • Doubled on doubling the concentration of sodium hydroxide
  • Halved on reducing the concentration of alkyl halide to one half
  • Decreased on increasing the temperature of the reaction
  • Unaffected by increasing the temperature of the reaction
The rates of reactions increase with increase of temperature because
  • activation energy of the reacting molecules decreases
  • kinetic energy of the product molecules increases
  • the fraction of the reacting molecules possessing an energy equal to the activation energy or more increases
  • the collisions between molecules decrease
The rate constant (k’) of one of the reaction is found to be double that of the rate constant (k’’) of another reaction. Then the relationship between the corresponding activation energies of the two reactions (Ea’ and Ea’’) can be represented as
  • Ea’ > Ea’’
  • Ea’ < Ea’’
  • Ea’ = Ea’’
  • Ea’ = 4Ea’’
What will be the order of the reaction if doubling the concentration of a reactant increases the rate by a factor of 4 and trebling the concentration of the reactant by a factor of 9?
  • First order
  • Zero order
  • Second order
  • Third order
Select the law that corresponds to data shown for the following reaction
A + B → Products
Exp. [A] [B] initial rate
1 0.012 0.035 0.1
2 0.024 0.070 0.8
3 0.024 0.035 0.1
4 0.012 0.070 0.8
  • rate = k [B]3
  • rate = k [B]3
  • rate = k [A] [B]3
  • rate = k [A]2 [B]2
The one which is unimolecular reaction is

  • Chemistry-Chemical Kinetics-1675.png
  • 2)
    Chemistry-Chemical Kinetics-1676.png

  • Chemistry-Chemical Kinetics-1677.png

  • Chemistry-Chemical Kinetics-1678.png

Chemistry-Chemical Kinetics-1679.png
  • 2 and 2 respectively
  • 2)
    Chemistry-Chemical Kinetics-1680.png

  • Chemistry-Chemical Kinetics-1681.png

  • Chemistry-Chemical Kinetics-1682.png
For an exothermic reaction, the energy of activation of the reactants is
  • equal to the energy of activation of products
  • less than the energy of activation of products
  • greater than the energy of activation of products
  • sometimes greater and sometimes less than that of the products

Chemistry-Chemical Kinetics-1685.png
  • a first order reaction
  • a second order reaction
  • independent of the initial concentration of the salt
  • a zero order reaction
Which of the following statement about the catalyst is true?
  • A catalyst accelerates the rate of reaction by bringing down the energy of activation
  • A catalyst does not participate in reaction mechanism
  • A catalyst makes the reaction more feasible by making ∆G more negative
  • A catalyst makes equilibrium constant more favorable for forward reaction
Activation energy of a chemical reaction can be determined by
  • evaluating rate constant at standard temperature
  • evaluating velocities of reaction at two different temperatures
  • evaluating rate constants at two different temperatures
  • changing concentration of reactants
For the reaction A → B, the rate law expression is: rate = k [A]. Which of the following statements is incorrect?
  • The reaction follows first order kinetics
  • The t1/2 of reaction depends on initial concentration of reactants
  • K is constant for the reaction at a constant temperature
  • The rate law provides a simple way of predicting the conc. of reactants and products at any time after the start of the reaction.
For a first order reaction, the plot of log k against 1/T is a straight line. The slope of the line is equal to

  • Chemistry-Chemical Kinetics-1686.png
  • 2)
    Chemistry-Chemical Kinetics-1687.png

  • Chemistry-Chemical Kinetics-1688.png

  • Chemistry-Chemical Kinetics-1689.png

Chemistry-Chemical Kinetics-1691.png

  • Chemistry-Chemical Kinetics-1692.png
  • 2)
    Chemistry-Chemical Kinetics-1693.png

  • Chemistry-Chemical Kinetics-1694.png

  • Chemistry-Chemical Kinetics-1695.png
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