JEE Main & Advanced Chemistry Chemical Kinetics / रासायनिक बलगतिकी Question Bank

done Topic Test - Chemical Kinetics Total Questions - 35

• question_answer1)
  The velocity constant of a reaction at 280 K is \[1.6\times {{10}^{-4}}\]. The velocity constant of the same reaction at 300 K is
  A)
  \[1.6\times {{10}^{-4}}\]                      done clear
  B)
  \[0.8\times {{10}^{-4}}\] done clear
  C)
  \[6.4\times {{10}^{-4}}\]          done clear
  D)
  \[3.2\times {{10}^{-4}}\] done clear
  View Solution play_arrow

• question_answer2)

  Decomposition of A follows first order kinetics by the following equation.

  \[4A(g)\xrightarrow{{}}B(g)+2C(g)\]

  If initially, total pressure was 800 mm of Hg and after 10 minutes it is found to be 650 mm of Hg. What is half-life of A? (Assume only A is present initially).

  A)
  10 mins done clear
  B)
  5 mins done clear
  C)
  7.5 mins done clear
  D)
  15 mins done clear
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• question_answer3)

  The following mechanism has been proposed for the exothermic catalyzed complex reaction

  \[A+BIAB\xrightarrow[{}]{{{k}_{1}}}AB+I\xrightarrow[{}]{{{k}_{2}}}Q+A\]

  If \[{{k}_{1}}\] is much smaller than \[{{k}_{2}},\] the most suitable qualitative plot of Potential Energy (PE) versus reaction coordinate (R.Co) for the above reaction.

  A)
                     done clear
  B)
  done clear
  C)
  done clear
  D)
  done clear
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• question_answer4)

  For the reaction \[A+2B\to \] products(started with concentrations taken in stoichiometric proportion), the experimentally determined rate law is \[-\frac{d[B]}{dt}=k\sqrt{[A]}\sqrt{[B]}\]

  The half time of the reaction would be

  A)
  \[\frac{\sqrt{2}\times 0.693}{k}\]             done clear
  B)
  \[\frac{0.693}{1/k}\] done clear
  C)
  \[\frac{0.693}{\sqrt{2}k}\]                      done clear
  D)
  not defined done clear
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• question_answer5)

  Two consecutive irreversible first order reaction can be represented by \[A\xrightarrow[{}]{{{k}_{1}}}B\xrightarrow[{}]{{{k}_{2}}}C\].

  The rate equation for A is integrated to obtain

  \[{{[A]}_{t}}={{[A]}_{0}}{{e}^{-{{k}_{1}}t}}\] and \[{{[B]}_{t}}=\frac{{{k}_{1}}[{{A}_{0}}]}{{{k}_{2}}-{{k}_{1}}}[{{e}^{-{{k}_{1}}t}}-{{e}^{-{{k}_{2}}t}}]\].

  At what time will B be present in the greatest concentration?

  A)
  \[{{t}_{\max }}=\frac{1}{{{k}_{1}}+{{k}_{2}}}\ln \frac{{{k}_{2}}}{{{k}_{1}}}\]      done clear
  B)
  \[{{t}_{\max }}=\frac{1}{{{k}_{1}}+{{k}_{2}}}\ln \frac{{{k}_{2}}}{{{k}_{1}}}\] done clear
  C)
  \[{{t}_{\max }}=\frac{1}{{{k}_{2}}+{{k}_{1}}}\ln \frac{{{k}_{1}}}{{{k}_{2}}}\]      done clear
  D)
  None of these done clear
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• question_answer6)

  Figure shows a graph in \[{{\log }_{10}}\,k\,vs\,\frac{1}{T}\] where, k is rate constant and T is temperature. The straight line BC has slope, \[\tan \,\theta \,=-\frac{1}{2.303}\] and an intercept of 5 on y-axis. Thus, \[{{E}_{a}},\] the energy of activation, is

  A)
  4.606 cal                       done clear
  B)
  \[\frac{0.2}{2.303}cal\] done clear
  C)
  2 cal done clear
  D)
  None of these done clear
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• question_answer7)

  In a gaseous phase reaction,

  \[{{A}_{2}}(g)\,\xrightarrow{\,}\,B(g)\,+\frac{1}{2}\,(g),\]

  the increase in pressure from 100 mm to 120 mm is noticed in 5 min. The rate of disappearance of \[{{A}_{2}}\] in mm \[{{\min }^{-1}}\] is

  A)
  4                                  done clear
  B)
  8    done clear
  C)
  16                                 done clear
  D)
  2 done clear
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• question_answer8)

  A reactant [a] forms two products

  \[A\xrightarrow{{{k}_{1}}}B\] Activation energy \[{{E}_{{{a}_{1}}}}\]

  \[A\xrightarrow{{{k}_{2}}}C\] Activation energy \[E{{\,}_{{{a}_{2}}}}\]

  If \[{{E}_{{{a}_{2}}}}=2{{E}_{{{a}_{1}}}},\] then \[{{k}_{1}}\] and \[{{k}_{2}}\] will be related as

  A)
  \[{{k}_{2}}={{k}_{1}}{{e}^{-{{E}_{{{a}_{1}}}}/RT}}\]       done clear
  B)
  \[{{k}_{2}}={{k}_{1}}{{e}^{-{{E}_{{{a}_{2}}}}/RT}}\] done clear
  C)
  \[{{k}_{1}}={{k}_{2}}{{e}^{-{{E}_{{{a}_{1}}}}/RT}}\]       done clear
  D)
  \[{{k}_{1}}=2{{k}_{2}}{{e}^{{{E}_{{{a}_{2}}}}/RT}}\] done clear
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• question_answer9)
  Two substances A and B are present such that\[[{{A}_{0}}]=4[{{B}_{0}}]\] and half-life of A is 5 minute and that of B is 15 min. If they start decaying at the same time following 1st order kinetics, how much time later will the concentration of both of them would be same?
  A)
  15 min     done clear
  B)
  10 min done clear
  C)
  5 min                done clear
  D)
  12 min done clear
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• question_answer10)

  In the reversible reaction,

  \[2N{{O}_{2}}{{N}_{2}}{{O}_{4}}\]

  the rate of disappearance of \[N{{O}_{2}}\] is equal to

  A)
  \[\frac{2{{k}_{1}}}{{{k}_{2}}}\,{{[N{{O}_{2}}]}^{2}}\]                    done clear
  B)
  \[2{{k}_{1}}\,{{[N{{O}_{2}}]}^{2}}-2{{k}_{2}}\,[{{N}_{2}}{{O}_{4}}]\] done clear
  C)
  \[2{{k}_{1}}{{[N{{O}_{2}}]}^{2}}-{{k}_{2}}[{{N}_{2}}{{O}_{4}}]\] done clear
  D)
  \[(2{{k}_{1}}-{{k}_{2}})\,[N{{O}_{2}}]\] done clear
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• question_answer11)
  For the\[2A(g)\xrightarrow{\,}\,3B(g),\,{{t}_{1/2}}=12\,\min \]. Initial pressure exerted by A is 640 mm of Hg. The pressure of the reaction mixture after the time period of 36 min will be
  A)
  560 mm Hg      done clear
  B)
  680 mm Hg       done clear
  C)
  920 mm Hg       done clear
  D)
  600 mm Hg done clear
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• question_answer12)

  A decomposes as

  The rate of disappearance of B, taking 4M concentration of A is equal to

  A)
  \[1.6\times {{10}^{-3}}M{{s}^{-1}}\]  done clear
  B)
  \[6.4\times {{10}^{-3}}M{{s}^{-1}}\] done clear
  C)
  \[3.2\times {{10}^{-3}}M{{s}^{-1}}\] done clear
  D)
  insufficient to calculate done clear
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• question_answer13)

  \[(aq)\xrightarrow{{}}B(aq)+C(aq)\] is a first order reaction.

  Time t \[\infty \] Moles of reagent \[{{x}_{1}}\] \[{{x}_{2}}\]

  Reaction progress is measured with the help of titration of reagent P, if all A, B and C reacted with reagent have n factors \[\left[ \text{n factor}:n=\frac{mol.wt.}{eq.wt.} \right]\] in the ratio 1 : 2 : 3 with the reagent. The k in terms of t, \[{{x}_{1}}\] and \[{{x}_{2}}\] is

  A)
  \[k=\frac{1}{t}\ln \left( \frac{{{x}_{2}}}{{{x}_{2}}-{{x}_{1}}} \right)\]  done clear
  B)
  \[k=\frac{1}{t}\ln \left( \frac{2{{x}_{2}}}{{{x}_{2}}-{{x}_{1}}} \right)\] done clear
  C)
  \[k=\frac{1}{t}\ln \left( \frac{4{{x}_{2}}}{5({{x}_{2}}-{{x}_{1}})} \right)\] done clear
  D)
  \[k=\frac{1}{t}\ln \left( \frac{8{{x}_{2}}}{{{x}_{2}}-{{x}_{1}}} \right)\] done clear
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• question_answer14)
  The reaction cis\[-X\text{trans}-X\] is first order in both directions. At \[\text{25}{}^\circ \text{C,}\] the equilibrium constant is 0.10 and the rate constant \[{{k}_{f}}=3\times {{10}^{-4}}{{s}^{-1}}\]. In an experiment starting with the pure cis-form, how long would it take for half of the equilibrium amount of the trans-isomer to be formed?
  A)
  150 s                             done clear
  B)
  200 s done clear
  C)
  240 s                 done clear
  D)
  210 s done clear
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• question_answer15)

  \[A\to B;\,\,\,\,\,\,\,\,\,\,\,\,\,{{k}_{A}}={{10}^{15}}{{e}^{-2000/T}}\]

  \[C\to D;\,\,\,\,\,\,\,\,\,\,\,\,\,{{k}_{C}}={{10}^{14}}{{e}^{-1000/T}}\]

  Temperature T kelvin at which \[(\,{{k}_{A}}={{k}_{C}})\] is:

  A)
  1000 K              done clear
  B)
  2000 K done clear
  C)
  (2000/2.303) K   done clear
  D)
  (1000/2.303) K done clear
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• question_answer16)
  The acid catalyzed hydrolysis of an organic, compound 'A' at \[30{}^\circ C\] has a time for half change of 100 minute when carried out in a buffer solution at \[(pH=5)\] and 10 minute when carried out at \[(pH=4)\]. Both times of half change are independent of the initial concentration of A. If rate constant K is defined by \[\frac{-d[A]}{dt}=K{{[A]}^{a}}{{[{{H}^{+}}]}^{b}},\] the values of a and b respectively are
  A)
  1, 1   done clear
  B)
  1, 2 done clear
  C)
  0, 1                   done clear
  D)
  1, 0 done clear
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• question_answer17)
  Which of the following statements regarding the molecularity of a reaction are correct?
  A)
  It is the number of molecules of the reactants taking part in a single step chemical reaction done clear
  B)
  It is calculated from reaction mechanism done clear
  C)
  It depends on the rate determining step in the reaction done clear
  D)
  It always whole number. done clear
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• question_answer18)
  A reaction that is of the first order with respect to 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 \[0.05\,mol\,{{l}^{-1}}\]
  A)
  0.384 min done clear
  B)
  0.15 min done clear
  C)
  3 min                done clear
  D)
  3.84 min done clear
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• question_answer19)
  For the reaction \[X+Y\to Z,\] following kinetic data was obtained :

  Initial [X]M	Initial [Y]M	Initial rate M \[\mathbf{mi}{{\mathbf{n}}^{\mathbf{-1}}}\]
  0.4	2.0	\[6.2\times {{10}^{-3}}\]
  0.8	2.0	\[2.48\times {{10}^{-2}}\]
  0.4	4.0	\[1.24\times {{10}^{-2}}\]
  0.5	1.5	?

  Calculate initial rate in the last experiment
  A)
  \[\text{4}.\text{36}\times \text{l}{{0}^{-\text{3}}}\]                   done clear
  B)
  \[\text{5}.\text{81}\times \text{l}{{0}^{-\text{3}}}\] done clear
  C)
  \[\text{7}.\text{27}\times \text{l}{{0}^{-\text{3}}}\] done clear
  D)
  \[\text{9}.\text{69}\times \text{l}{{0}^{-\text{3}}}\] done clear
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• question_answer20)
  \[6{{I}^{-}}(aq)+Br{{O}_{3}}^{-}(aq)+6{{H}^{+}}(aq)\xrightarrow{{}}3{{I}_{2}}(aq)+\] \[B{{r}^{-}}(aq)+3{{H}_{2}}O(\ell )\] these data were obtained when this reaction was studies.

  \[[{{I}^{-}}],M\]	\[[Br{{O}_{3}}^{-}],M\]	\[[{{H}^{+}}],M\]	Reaction rate \[(mol\,{{L}^{-1}}{{s}^{-1}})\]
  0.0010	0.0020	0.010	\[8.0\times {{10}^{-5}}\]
  0.0020	0.0020	0.010	\[1.6\times {{10}^{-4}}\]
  0.0020	0.0040	0.010	\[1.6\times {{10}^{-4}}\]
  0.0010	0.0040	0.020	\[1.6\times {{10}^{-4}}\]

  What is the units of the rate constant for this reaction?
  A)
  \[{{s}^{-1}}\]                          done clear
  B)
  \[mol\,\,{{L}^{-1}}{{s}^{-1}}\] done clear
  C)
  \[L\,\,mo{{l}^{-1}}{{s}^{-1}}\] done clear
  D)
  \[{{L}^{2}}\,\,mo{{l}^{-2}}{{s}^{-1}}\] done clear
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• question_answer21)
  For a first-order homogeneous gaseous reaction \[A\to 2B+C,\] if the total pressure after time t was \[{{P}_{t}}\] and after long time \[(t\to \infty )\] was \[{{P}_{\infty }}\] then k in terms of \[{{P}_{t}},\,{{P}_{\infty }}\] and t is:
  A)
  \[k=\frac{2.303}{t}\log \left( \frac{{{P}_{\infty }}}{{{P}_{\infty }}-{{P}_{t}}} \right)\] done clear
  B)
  \[k=\frac{2.303}{t}\log \left( \frac{2{{P}_{\infty }}}{{{P}_{\infty }}-{{P}_{t}}} \right)\] done clear
  C)
  \[k=\frac{2.303}{t}\log \left( \frac{2{{P}_{\infty }}}{3\left( {{P}_{\infty }}-{{P}_{t}} \right)} \right)\] done clear
  D)
  None of these done clear
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• question_answer22)
  The main function of a catalyst in speeding up a reaction is
  A)
  To increase the rate of the forward reaction done clear
  B)
  To change the reaction path so as to decrease the energy of activation for the reaction done clear
  C)
  To reduce the temperature at which the reaction can occur done clear
  D)
  To increase the energy of the molecules of the reactants done clear
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• question_answer23)
  In a certain reaction, 10% of the reactant decomposes in 1 h, 20% in 2 h, 30% in 3 h, and so on. The dimensions of the rate constant is:
  A)
  \[{{h}^{-1}}\]                          done clear
  B)
  \[mol/\left( L\,s \right)\]      done clear
  C)
  L / (mol s)                      done clear
  D)
  mol/s done clear
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• question_answer24)

  A hypothetical reaction:

  \[{{A}_{2}}+{{B}_{2}}\xrightarrow{{}}2AB\] follows mechanism as given below:

  \[{{A}_{2}}A+A\]............ (fast)

  (\[{{k}_{c}}\] is equilibrium constant)

  \[{{A}_{2}}+{{B}_{2}}\xrightarrow{{{k}_{1}}}AB+B\] ..............(slow)

  (\[{{k}_{1}}\] rate constant)

  \[A+BAB\] .................. (fast)

  (\[{{k}_{2}},{{k}_{3}}\] are rate constant)

  Give the rate law.

  A)
  \[r={{k}_{1}}\sqrt{{{k}_{c}}}\,{{[{{A}_{2}}]}^{1/2}}[{{B}_{2}}]\]   done clear
  B)
  \[r=\frac{{{k}_{1}}}{{{k}_{c}}}\,{{[{{A}_{2}}]}^{1/2}}[{{B}_{2}}]\] done clear
  C)
  \[r=\sqrt{{{k}_{1}}{{k}_{c}}}\,\,{{[{{A}_{2}}]}^{1/2}}[{{B}_{2}}]\] done clear
  D)
  \[r=\frac{{{k}_{1}}}{\sqrt{{{k}_{c}}}}\,{{[{{A}_{2}}]}^{1/2}}[{{B}_{2}}]\] done clear
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• question_answer25)
  In presence of catalyst, the activation energy is lowered by 3 kcal at \[27{}^\circ C\]. Hence, the rate of reaction will increase by
  A)
  32 times           done clear
  B)
  243 times done clear
  C)
  2 times             done clear
  D)
  148 times done clear
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• question_answer26)

  A gaseous compound A reacts by three independent first-order processes (as shown in the figure) with rate constants \[2\times {{10}^{-3}},\,3\times {{10}^{-3}}\] and \[1.93\times {{10}^{-3}}{{s}^{-1}}\] products B, C and D respectively. If initially pure A  was taken in a closed container with P = 8 atm, then the partial pressure of B (in atm) after 100 s from start of experiment will be:

  A)
  0.288                            done clear
  B)
  0.577        done clear
  C)
  1.154   done clear
  D)
  None of these done clear
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• question_answer27)
  In a first-order reaction, the reacting substance has half-life period of 10 min. What fraction of the substance will be left after an hour the reaction has occurred?
  A)
  1/6 of initial concentration       done clear
  B)
  1/64 of initial concentration done clear
  C)
  1/12 of initial concentration      done clear
  D)
  1/32 of initial concentration done clear
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• question_answer28)

  A graph of volume of hydrogen released vs time for the reaction between zinc and dil. HCl is given in figure. On the basis of this mark the correct option.

  A)
  Average rate upto 40s is \[\frac{{{V}_{3}}-{{V}_{2}}}{40}\] done clear
  B)
  Average rate upto 40 seconds is \[\frac{{{V}_{3}}-{{V}_{2}}}{40-30}\] done clear
  C)
  Average rate upto 40 seconds is \[\frac{{{V}_{3}}}{40}\] done clear
  D)
  Average rate upto 40 seconds is \[\frac{{{V}_{3}}-{{V}_{1}}}{40-20}\] done clear
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• question_answer29)
  If a first-order reaction is completed to the extent of 60% and 20% in time intervals, \[{{t}_{1}}\] and \[{{t}_{2}},\] what is the ratio \[{{t}_{1}}:{{t}_{2}}\]
  A)
  6.32                              done clear
  B)
  5.58          done clear
  C)
  4.11        done clear
  D)
  8.33 done clear
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• question_answer30)
  In any unimolecular reaction
  A)
  only one reacting species is involved in the rate determining step done clear
  B)
  the order and the molecularity of slowest step are equal to one done clear
  C)
  the molecularity of the reaction is one and order is zero done clear
  D)
  both molecularity and order of the reaction are one done clear
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• question_answer31)

  Consider the following case of completing 1st order reactions.

  After the start of the reaction at t = 0 with only A, the [C] is equal to the [D] at all times. The time in which all three concentrations will be equal is given by -

  A)
  \[t=\frac{1}{2{{k}_{1}}}\ell n3\]                        done clear
  B)
  \[t=\frac{1}{2{{k}_{2}}}\ell n\,3\] done clear
  C)
  \[t=\frac{1}{3{{k}_{1}}}\ell n2\]                        done clear
  D)
  \[t=\frac{1}{3{{k}_{1}}}\ell n2\] done clear
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• question_answer32)
  The forward rate constant for the reversible gaseous reaction \[{{C}_{2}}{{H}_{6}}2C{{H}_{3}}\] is\[3.14\times {{10}^{+2}}{{s}^{-1}}\] at 200 K. What is the rate constant for the backward reaction at this temperature, if \[{{10}^{-5}}\] moles of \[C{{H}_{3}}\] and 100 mol of \[{{C}_{2}}{{H}_{6}}\] are present in 10 L vessel at equilibrium?
  A)
  \[1.57\times {{10}^{14}}Lmo{{l}^{-1}}{{s}^{-1}}\] done clear
  B)
  \[3.14\times {{10}^{15}}Lmo{{l}^{-1}}{{s}^{-1}}\] done clear
  C)
  \[1.57\times {{10}^{7}}Lmo{{l}^{-1}}{{s}^{-1}}\] done clear
  D)
  \[3.14\times {{10}^{10}}Lmo{{l}^{-1}}{{s}^{-1}}\] done clear
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• question_answer33)
  In a reaction involving one single reactant, the fraction of the reactant consumed may be defined as \[f=\left[ 1-\left( C/{{C}_{0}} \right) \right],\] where \[{{C}_{0}}\] and C are the concentrations of the reactant at the start and after time t. For a first-order reaction:
  A)
  \[\frac{df}{dt}=k\left( 1-f \right)\] done clear
  B)
  \[-\frac{df}{dt}=kf\] done clear
  C)
  \[-\frac{df}{dt}=k\left( 1-f \right)\]            done clear
  D)
  \[\frac{df}{dt}=kf\] done clear
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• question_answer34)
  The inversion of cane sugar proceeds with half-life of 500 min at pH = 5 for any concentration of sugar. However, if pH = 6, the half-life changes to 50 min. The rate law expression for sugar inversion can be written as:
  A)
  \[r=K{{\left[ sugar \right]}^{2}}{{\left[ {{H}^{+}} \right]}^{0}}\]             done clear
  B)
  \[r=K{{\left[ sugar \right]}^{1}}{{\left[ {{H}^{+}} \right]}^{0}}\] done clear
  C)
  \[r=K{{\left[ sugar \right]}^{1}}{{\left[ {{H}^{+}} \right]}^{1}}\] done clear
  D)
  \[r=K{{\left[ sugar \right]}^{0}}{{\left[ {{H}^{+}} \right]}^{0}}\] done clear
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• question_answer35)

  Given is the information:

  Reaction 1 :       \[k=A{{e}^{-{{E}_{1}}/RT}}\]

  Reaction 2 :       \[k'=A{{e}^{-{{E}_{2}}/RT}}\]

  If \[{{E}_{1}}=2{{E}_{2}},\] then the ratio \[\ell n\left[ \frac{{{k}_{T}}+10k}{{{k}_{T}}} \right]\] for the reaction will be

  A)
  Equal to that of reaction 2 done clear
  B)
  greater than that of reaction 2 done clear
  C)
  lesser than that of reaction 2 done clear
  D)
  may be greater or lesser than reaction 2 depending upon the temperature T. done clear
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