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Chemical Kinetics · Question 11

JEE Main 2026 (Online) 2nd April Morning ShiftNumericalMedium📈 Topic in 29% papers+4
1

For reaction A P, rate constant k = 1.5 103 s-1 at 27°C If activation energy for the above reaction is 60 kJ mol-1, then the temperature (in °C) at which rate constant, k = 4.5 103 s-1 is . (Nearest integer) Given : log 2 = 0.30, log 3 = 0.48, R = 8.3 J K-1 mol-1, ln 10 = 2.3

Answer

41

Solution

T1 = 27 + 273 = 300 K, k2k1 = 4.5 1031.5 103 = 3

k2k1 = EaR ( 1T1- 1T2 )

⇒ 3 = 2.3 3 = 2.3 0.48 = 1.104

⇒ 1.104 = 600008.3 ( 1300- 1T2 )

⇒ 1300- 1T2 = 1.104 8.360000

⇒ 1300- 1T2 = 1.527 10-4

⇒ 1T2 = 3.333 10-3 - 0.153 10-3

⇒ 1T2 = 3.181 10-3 K-1

⇒ T2 = 314.4 K

∴ Temperature = 314.4 − 273 = 41.4°C ≈ 41°C

Answer: 41

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2

Consider the reaction aX bY, for which the rate constant at 30°C is 1 10-3 mol-1 L s-1. Which of the following statements are true? Choose the correct answer from the options given below:

  1. A and B Only
  2. A, B and C Only
  3. A, B, D and E Only
  4. C and D Only
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3

Consider the following gas phase reaction being carried out in a closed vessel at 25°C. 2A(g) 4B(g) + C(g) array|c|c| time (min) & total pressure of the system (mm Hg) \ 30 & 300 \ & 600 \ array The pressure of C(g) at 30 minutes time interval would be mm Hg. (nearest integer)

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4

An organic compound undergoes first order decomposition. The time taken for decomposition to ( 18 )th and ( 110 )th of its initial concentration are t1/8 and t1/10 respectively. What is the value of t1/8 t1/10 10? ( 2 = 0.3)

  1. 30
  2. 9
  3. 3
  4. 0.9
JEE Main 2026 (Online) 28th January Morning Shift
5

A → B (first reaction) C → D (second reaction) Consider the above two first-order reactions. The rate constant for first reaction at 500 K is double of the same at 300 K. At 500 K, 50% of the reaction becomes complete in 2 hours. The activation energy of the second reaction is half of that of first reaction. If the rate constant at 500 K of the second reaction becomes double of the rate constant of first reaction at the same temperature; then rate constant for the second reaction at 300 K is 10-1 hour-1 (nearest integer).

JEE Main 2026 (Online) 28th January Evening Shift
6

A D is an endothermic reaction occurring in three steps (elementary). (i) A B, Hi = +ve (ii) B C, Hii = -ve (iii) C D, Hiii = -ve Which of the following graphs between potential energy (y-axis) vs reaction coordinate (x-axis) correctly represents the reaction profile of A D?

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
JEE Main 2026 (Online) 24th January Morning Shift
7

At 27 in presence of a catalyst, activation energy of a reaction is lowered by 10 kJ mol-1. The logarithm of ratio of k (catalysed)k (uncatalysed) is.... (Consider that the frequency factor for both the reactions is same)

  1. 1.741
  2. 0.1741
  3. 17.41
  4. 3.482
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8

The half-life of 65Zn is 245 days. After x days, 75\% of original activity remained. The value of x in days is . (Nearest integer) (Given: 3 = 0.4771 and 2 = 0.3010)

JEE Main 2026 (Online) 24th January Evening Shift
9

For the thermal decomposition of reactant AB(g), the following plot is constructed. [figure] The half-life of the reaction is 'x' min. x = min. (Nearest integer)

JEE Main 2026 (Online) 23rd January Morning Shift
10

[figure] Given above is the concentration vs time plot for a dissociation reaction : A nB. Based on the data of the initial phase of the reaction (initial 10 min), the value of n is .

  1. 2
  2. 5
  3. 4
  4. 3
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11

Observe the following reactions at T(K). I. A products. II. 5Br-(aq) + BrO3-(aq) + 6H+(aq) 3Br2(aq) + 3H2O(l) Both the reactions are started at 10.00 am. The rates of these reactions at 10.10 am are same. The value of - [Br-] t at 10.10 am is 2 10-4 mol L-1 min-1. The concentration of A at 10.10 am is 10-2 mol L-1. What is the first order rate constant (in min-1) of reaction I?

  1. 4 10-3
  2. 2 10-3
  3. 10-3
  4. 10-2
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