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Chemical Kinetics

JEE Main 2026 (Online) 22nd January Morning ShiftMCQEasy📈 Topic in 16% papers+4−1
Ques. 1JEE Main 2026, 22 January (Morning Shift)

A product (First order reaction). Three sets of experiments were performed for a reaction under similar experimental conditions: Run 1 100 mL of 10 M solution of reactant A Run 2 200 mL of 10 M solution of reactant A Run 3 100 mL of 10 M solution of reactant A + 100 mL of H2O added. The correct variation of rate of reaction is

  1. Run 1 = Run 2 = Run 3
  2. Run 3 < Run 1 < Run 2
  3. Run 1 < Run 2 < Run 3
  4. Run 3 < Run 1 = Run 2

Answer

(4) Run 3 < Run 1 = Run 2

Solution

For a first order reaction: Rate = k[A]

Run 1: [A] = 10 M Rate = 10k

Run 2: [A] = 10 M (volume does not change concentration) Rate = 10k

Run 3: on adding 100 mL water, total volume = 200 mL

[A] = 10 100200 = 5 M Rate = 5k

Run 3 < Run 1 = Run 2

Answer: (4)

Keep practising — Chemical Kinetics

Ques. 2JEE Main 2026, 22 January (Morning Shift)

The temperature at which the rate constants of the given below two gaseous reactions become equal is K. (Nearest integer) X Y, k1 = 106 e -30000T P Q, k2 = 104 e -24000T Given : 10 = 2.303

Ques. 3JEE Main 2026, 22 January (Evening Shift)

Correct statements regarding Arrhenius equation among the following are : Choose the correct answer from the options given below :

  1. A and B Only
  2. B and D Only
  3. B and C Only
  4. A and C Only
Ques. 4JEE Main 2026, 22 January (Evening Shift)

Consider A k1 B and C k2 D are two reactions. If the rate constant (k1) of the A B reaction can be expressed by the following equation 10 k = 14.34 - 1.5 104T/K and activation energy of C D reaction (Ea2) is 15th of the A B reaction (Ea1), then the value of (Ea2) is kJ mol-1. (Nearest Integer)

Ques. 5JEE Main 2026, 21 January (Morning Shift)

Pre-exponential factors of two different reactions of same order are identical. Let activation energy of first reaction exceed the activation energy of second reaction by 20 kJ mol-1. If k1 and k2 are the rate constants of first and second reaction respectively at 300 K, then k2k1 will be . (nearest integer) [R = 8.3 J K-1 mol-1]

Ques. 6JEE Main 2026, 21 January (Evening Shift)

Decomposition of A is a first order reaction at T(K) and is given by A(g) B(g) + C(g). In a closed 1 L vessel, 1 bar A(g) is allowed to decompose at T(K). After 100 minutes, the total pressure was 1.5 bar. What is the rate constant (in min-1) of the reaction? ( 2 = 0.3)

  1. 6.9 10-4
  2. 6.9 10-3
  3. 6.9 10-1
  4. 6.9 10-2
Ques. 7JEE Main 2025, 8 April (Evening Shift)

In a first order decomposition reaction, the time taken for the decomposition of reactant to one fourth and one eighth of its initial concentration are t1 and t2 (s), respectively. The ratio t1/t2 will be:

  1. 43
  2. 32
  3. 34
  4. 23
Ques. 8JEE Main 2025, 7 April (Morning Shift)

A person's wound was exposed to some bacteria and then bacterial growth started to happen at the same place. The wound was later treated with some antibacterial medicine and the rate of bacterial decay (r) was found to be proportional with the square of the existing number of bacteria at any instance. Which of the following set of graphs correctly represents the 'before' and 'after' situation of the application of the medicine? [Given: N = No. of bacteria, t = time, bacterial growth follows 1st order kinetics.]

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
Ques. 9JEE Main 2025, 7 April (Morning Shift)

Reaction A(g) 2B(g) + C(g) is a first order reaction. It was started with pure A. array|c|c| t/min & Pressure of system at time t/mm Hg \ 10 & 160 \ & 240 \ array Which of the following option is incorrect?

  1. Initial pressure of A is 80 mm Hg
  2. The reaction never goes to completion
  3. Partial pressure of A after 10 minutes is 40 mm Hg
  4. Rate constant of the reaction is 1.693 min-1
Ques. 10JEE Main 2025, 7 April (Evening Shift)

A(g) B(g) + C(g) is a first order reaction. array|l|c|c| Time & t & \ Psystem & Pt & P \ array The reaction was started with reactant A only. Which of the following expressions is correct for rate constant k?

  1. k = 1t P Pt
  2. k = 1t P 2(P - Pt)
  3. k = 1t 2(P - Pt)Pt
  4. k = 1t P (P - Pt)
Ques. 11JEE Main 2025, 4 April (Morning Shift)

For A2 + B2 2AB Ea for forward and backward reaction are 180 and 200 kJ mol-1 respectively. If catalyst lowers Ea for both reactions by 100 kJ mol-1. Which of the following statement is correct?

  1. Catalyst does not alter the Gibbs energy change of a reaction.
  2. The enthalpy change for the reaction is +20 kJ mol-1.
  3. Catalyst can cause non-spontaneous reactions to occur.
  4. The enthalpy change for the catalysed reaction is different from that of uncatalysed reaction.

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