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Chemical Kinetics · Question 3

JEE Main 2026 (Online) 6th April Evening ShiftNumericalEasy📈 Topic in 29% papers+4
1

Decomposition of a hydrocarbon follows the equation k = (5.5 1011 s-1) e-28000 K/T. The activation energy of reaction is kJ mol-1. (Nearest Integer) Given : R = 8.3 J K-1 mol-1

Answer

232

Solution

Arrhenius equation: k = Ae-Ea/RT

Comparing with k = (5.5 1011 s-1) e-28000 K/T:

EaR = 28000 K

⇒ Ea = 28000 × 8.3 = 232400 J mol-1

⇒ Ea ≈ 232 kJ mol-1

Answer: 232

JEE Main 2026 (Online) 6th April Evening Shift

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2

First order gas phase reaction A B + C pi = initial pressure of gas A, pt = total pressure of the reaction mixture at time t Expression of rate constant (k) is

  1. 1t pi2pi - pt
  2. 1t 2pipi - pt
  3. 1t pi3pi - 2pt
  4. 1t 3pi4pi - pt
JEE Main 2026 (Online) 5th April Morning Shift
3

If the half life of a first order reaction is 6.93 minutes then the time required for completion of 99% of the reaction will be minutes. (Given : log 2 = 0.3010)

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4

For a reaction A → P at T K, the half life (t1/2) is plotted as a function of initial concentration [A]0 of A as given below. [figure] The value of x in the given figure is s (Nearest integer)

JEE Main 2026 (Online) 5th April Evening Shift
5

Consider the first order reaction R P. The fraction of molecules decomposed in the given first order reaction can be expressed as

  1. 1 - ek1t
  2. 1 + ek1t
  3. 1 + e-k1t
  4. 1 - e-k1t
JEE Main 2026 (Online) 4th April Morning Shift
6

Consider the given graph showing variation of reactant concentration with time. Three different reactions were started with identical initial concentration of reactants. Which of the following statement is correct? [figure]

  1. The order of all the three reactions is same.
  2. The rate constant of reaction 3 is larger than the rate constant of reaction 2 if the order of reaction is same for both.
  3. The SI unit of rate constant of reaction 1 is s-1.
  4. Thermal decomposition of HI on gold surface is an example of reaction 2.
JEE Main 2026 (Online) 4th April Evening Shift
7

For a first order reaction A B arrayll t/min & [A]/M \ 0 & 0.6500 \ x & 0.0650 \ 20 & 0.00065 array x = min. (Nearest integer)

JEE Main 2026 (Online) 4th April Evening Shift
8

t100\% is the time required for the 100% completion of the reaction while t1/2 is the time required for 50% of the reaction to be completed. Which of the following option correctly represents the relation between t100\% and t1/2 for zero and first order reactions respectively ?

  1. t100\% = (t1/2)2 and t100\% = (t1/2)-
  2. t100\% = 2t1/2 and t100\% = (t1/2)
  3. t100\% = 2t1/2 and t100\% = (2t1/2)2
  4. t100\% = (t1/2) and t100\% = 2t1/2
JEE Main 2026 (Online) 2nd April Morning Shift
9

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

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10

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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11

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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