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Chemical Kinetics

JEE Main 2025 (Online) 4th April Morning ShiftMCQEasy📈 Topic in 16% papers+4−1
Ques. 1JEE Main 2025, 4 April (Morning Shift)

Rate law for a reaction between A and B is given by r = k[A]n[B]m If concentration of A is doubled and concentration of B is halved from their initial value, the ratio of new rate of reaction to the initial rate of reaction ( r2r1 ) is

  1. (n-m)
  2. 2(n-m)
  3. 12m+n
  4. (m+n)

Answer

(2) 2(n-m)

Solution

r1 = k[A]n[B]m

r2 = k(2[A])n ( [B]2 )m

r2 = 2n 2-m k[A]n[B]m

r2r1 = 2(n-m)

Answer: (2)

Keep practising — Chemical Kinetics

Ques. 2JEE Main 2025, 4 April (Evening Shift)

Consider the following plots of log of rate constant k (log k) vs 1T for three different reactions. The correct order of activation energies of these reactions is : [figure]

  1. Ea2 > Ea1 > Ea3
  2. Ea1 > Ea3 > Ea2
  3. Ea3 > Ea2 > Ea1
  4. Ea1 > Ea2 > Ea3
Ques. 3JEE Main 2025, 4 April (Evening Shift)

Half life of zero order reaction A product is 1 hour, when initial concentration of reactant is 2.0 mol L-1. The time required to decrease concentration of A from 0.50 to 0.25 mol L-1 is :

  1. 0.5 hour
  2. 15 min
  3. 60 min
  4. 4 hour
Ques. 4JEE Main 2025, 3 April (Morning Shift)

In a reaction A + B C, initial concentrations of A and B are related as [A]0 = 8[B]0. The half-lives of A and B are 10 min and 40 min, respectively. If they start to disappear at the same time, both following first order kinetics, after how much time will the concentration of both the reactants be same?

  1. 20 min
  2. 40 min
  3. 80 min
  4. 60 min
Ques. 5JEE Main 2025, 3 April (Evening Shift)

Consider the following statements related to temperature dependence of rate constants. Identify the correct statements. Choose the correct answer from the options given below:

  1. A, C and D Only
  2. B, D and E Only
  3. B and C Only
  4. A and B Only
Ques. 6JEE Main 2025, 2 April (Morning Shift)

For the reaction A products. [figure] The concentration of A at 10 minutes is 10-3 mol L-1 (nearest integer). The reaction was started with 2.5 mol L-1 of A.

Ques. 7JEE Main 2025, 2 April (Evening Shift)

Reactant A converts to product D through the given mechanism (with the net evolution of heat): A B slow; H = +ve B C fast; H = -ve C D fast; H = -ve Which of the following represents the above reaction mechanism?

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
Ques. 8JEE Main 2025, 2 April (Evening Shift)

For the reaction A B the following graph was obtained. The time required (in seconds) for the concentration of A to reduce to 2.5 g L-1 (if the initial concentration of A was 50 g L-1) is . (Nearest integer) Given : 2 = 0.3010 [figure]

Ques. 9JEE Main 2025, 29 January (Morning Shift)

The reaction A2 + B2 2AB follows the mechanism: A2 k-1 k1 A + A (fast) A + B2 k2 AB + B (slow) A + B AB (fast) The overall order of the reaction is:

  1. 3
  2. 2.5
  3. 1.5
  4. 2
Ques. 10JEE Main 2025, 29 January (Evening Shift)

Drug X becomes ineffective after 50\% decomposition. The original concentration of drug in a bottle was 16 mg/mL which becomes 4 mg/mL in 12 months. The expiry time of the drug in months is . Assume that the decomposition of the drug follows first order kinetics.

  1. 12
  2. 3
  3. 6
  4. 2
Ques. 11JEE Main 2025, 28 January (Morning Shift)

array|c|c| [A]0/ mol L-1 & t1/2/min \ 0.100 & 200 \ 0.025 & 100 \ array For a given reaction R P, t1/2 is related to [A]0 as given in table. Given: 2 = 0.30 Which of the following is true? Choose the correct answer from the options given below:

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

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