Chemical Kinetics · JEE Main previous year questions

2022 14 questions

1. Q842022 · 29 Jul 2022 · Shift 2· Numerical answer

   Assuming $1\mu \mathrm{g}$ of trace radioactive element X with a half life of 30 years is absorbed by a growing tree. The amount of X remaining in the tree after 100 years is ____ $\times 10^{-1}\mu \mathrm{g}$. $[\text{Given : }\ln 10=2.303;\log 2=0.30]$

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   Answer: 1

2. Q852022 · 28 Jul 2022 · Shift 1· Numerical answer

   For the given first order reaction $$\text{A}\to \text{B}$$ the half life of the reaction is $0.3010\text{ min}$. The ratio of the initial concentration of reactant to the concentration of reactant at time $2.0\text{ min}$ will be equal to _________. (Nearest integer)

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   Answer: 100

3. Q862022 · 28 Jul 2022 · Shift 2· Numerical answer
   
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   Answer: 8

4. Q842022 · 27 Jul 2022 · Shift 2· Numerical answer

   $$\begin{array}{ccc}[A]& \to & [B]\\ \text{Reactant}& & \text{Product}\end{array}$$ If formation of compound $[\mathrm{B}]$ follows the first order of kinetics and after 70 minutes the concentration of $[\mathrm{A}]$ was found to be half of its initial concentration. Then the rate constant of the reaction is $x\times 10^{-6}{\mathrm{s}}^{-1}$. The value of $x$ is ____. (Nearest Integer)

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   Answer: 165

5. Q872022 · 26 Jul 2022 · Shift 1· Numerical answer

   For a reaction $\mathrm{A}\to 2\mathrm{B}+\mathrm{C}$ the half lives are $100\mathrm{s}$ and $50\mathrm{s}$ when the concentration of reactant $\mathrm{A}$ is $0.5$ and $1.0\mathrm{mol}{\mathrm{L}}^{-1}$ respectively. The order of the reaction is ____. (Nearest Integer)

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   Answer: 2

6. Q842022 · 25 Jul 2022 · Shift 2· Numerical answer
   
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   Answer: 2

7. Q842022 · 30 Jun 2022 · Shift 1· Numerical answer

   For the reaction $\mathrm{P}\to \mathrm{B}$, the values of frequency factor A and activation energy ${\mathrm{E}}_{\mathrm{A}}$ are $4\times 10^{13}{\text{ s}}^{-1}$ and $8.3{\text{ kJ mol}}^{-1}$ respectively. If the reaction is of first order, the temperature at which the rate constant is $2\times 10^{-6}{\text{ s}}^{-1}$ is ___________ $\times 10^{-1}\text{ K}$. (Given : $\ln 10=2.3$, $\mathrm{R}=8.3{\text{ J K}}^{-1}{\text{ mol}}^{-1}$, $\log 2=0.30$)

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   Answer: 225

8. Q842022 · 28 Jun 2022 · Shift 2· Numerical answer

   A radioactive element has a half life of 200 days. The percentage of original activity remaining after 83 days is ___________. (Nearest integer) (Given : antilog 0.125 = 1.333, antilog 0.693 = 4.93)

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   Answer: 75

9. Q852022 · 27 Jun 2022 · Shift 1· Numerical answer

   The rate constant for a first order reaction is given by the following equation: $$\ln k=33.24-\frac{2.0\times 10^{4}K}{T}$$ The activation energy for the reaction is given by ____ $\mathrm{kJ}\mathrm{mo}{\mathrm{l}}^{-1}$. (In nearest integer) (Given : $\mathrm{R}=8.3\mathrm{J}{\mathrm{K}}^{-1}\mathrm{mo}{\mathrm{l}}^{-1}$)

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   Answer: 166

10. Q872022 · 27 Jun 2022 · Shift 2· Numerical answer

    It has been found that for a chemical reaction with rise in temperature by $9\text{ K}$ the rate constant gets doubled. Assuming a reaction to be occurring at $300\text{ K}$, the value of activation energy is found to be ________ ${\text{kJ mol}}^{-1}$. [nearest integer] (Given $\ln 10=2.3$, $\text{R}=8.3{\text{ J K}}^{-1}{\text{ mol}}^{-1}$, $\log 2=0.30$)

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    Answer: 59

11. Q872022 · 26 Jun 2022 · Shift 2· Numerical answer

    Catalyst A reduces the activation energy for a reaction by $10\mathrm{kJ}\mathrm{mo}{\mathrm{l}}^{-1}$ at $300\mathrm{K}$. The ratio of rate constants, $\frac{k_{T,\text{Catalysed}}}{k_{T,\text{Uncatalysed}}}$ is ${\mathrm{e}}^x$. The value of $x$ is ____. [nearest integer] [Assume that the pre-exponential factor is same in both the cases. Given $\mathrm{R}=8.31\mathrm{J}{\mathrm{K}}^{-1}\mathrm{mo}{\mathrm{l}}^{-1}$]

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    Answer: 4

12. Q872022 · 25 Jun 2022 · Shift 1· Numerical answer

    For a given chemical reaction ${\gamma }_1\mathrm{A}+{\gamma }_2\mathrm{B}\to {\gamma }_3\mathrm{C}+{\gamma }_4\mathrm{D}$ Concentration of $\mathrm{C}$ changes from $10{\text{ mmol dm}}^{-3}$ to $20{\text{ mmol dm}}^{-3}$ in $10\text{ seconds}$. Rate of appearance of $\mathrm{D}$ is $1.5$ times the rate of disappearance of $\mathrm{B}$ which is twice the rate of disappearance $\mathrm{A}$. The rate of appearance of $\mathrm{D}$ has been experimentally determined to be $9{\text{ mmol dm}}^{-3}{\text{ s}}^{-1}$. Therefore, the rate of reaction is $\underline{}{\text{ mmol dm}}^{-3}{\text{ s}}^{-1}$. (Nearest Integer)

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    Answer: 1

13. Q832022 · 25 Jun 2022 · Shift 2· Numerical answer

    At 345 K, the half life for the decomposition of a sample of a gaseous compound initially at 55.5 kPa was 340 s. When the pressure was 27.8 kPa, the half life was found to be 170 s. The order of the reaction is ____________. [integer answer]

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    Answer: 0

14. Q652022 · 24 Jun 2022 · Shift 2

    For a first order reaction, the time required for completion of 90% reaction is 'x' times the half life of the reaction. The value of 'x' is (Given : ln 10 = 2.303 and log 2 = 0.3010)

    1. A.1.12
    2. B.2.43
    3. C.3.32
    4. D.33.31
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    Answer: C