JEE Main & Advanced Chemistry Chemical Kinetics / रासायनिक बलगतिकी Sample Paper

done Topic Test - Chemical Kinetics Total Questions - 35    [Download]

• 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 Answer 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
  View Answer play_arrow

• 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
  View Answer play_arrow

• 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
  View Answer play_arrow

• 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
  View Answer play_arrow

• 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
  View Answer play_arrow

• 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
  View Answer play_arrow

• 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
  View Answer play_arrow

• 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
  View Answer play_arrow

• 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
  View Answer play_arrow

• 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
  View Answer play_arrow

• 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
  View Answer play_arrow

• 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
  View Answer play_arrow

• 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
  View Answer play_arrow

• 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
  View Answer play_arrow

• 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
  View Answer play_arrow

• 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
  View Answer play_arrow

• 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
  View Answer play_arrow

• 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
  View Answer play_arrow

• 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
  View Answer play_arrow

• 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
  View Answer play_arrow

• 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
  View Answer play_arrow

• 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
  View Answer play_arrow

• 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
  View Answer play_arrow

• 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
  View Answer play_arrow

• 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
  View Answer play_arrow

• 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
  View Answer play_arrow

• 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
  View Answer play_arrow

• 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
  View Answer play_arrow

• 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
  View Answer play_arrow

• 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
  View Answer play_arrow

• 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
  View Answer play_arrow

• 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
  View Answer play_arrow

• 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
  View Answer play_arrow

• 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
  View Answer play_arrow