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Which of the following statements are correct about half life period ?
  • a)
    It is proportional to initial concentration for a zero order reaction.
  • b)
    Average life = 1.44 times half life for a first order reaction.
  • c)
    Time of 75% reaction is thrice of half life period in second order reaction.
  • d)
    99.9% reaction which is first order, takes place in 100 minutes if the rate constant of the reaction is 0.0693 min-1.
Correct answer is option 'A,B,C,D'. Can you explain this answer?
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Verified Answer
Which of the following statements are correct about half life period ?...
(A) For zero order reaction

⇒ t1/2 α a0 (initial concentration)
(B) For first order reaction
Average life = 1.44 × half life
(C) For IInd order reaction



t99.9  = 100 min
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Most Upvoted Answer
Which of the following statements are correct about half life period ?...
Explanation:

a) It is proportional to initial concentration for a zero order reaction.
In a zero-order reaction, the rate of reaction is independent of the concentration of the reactant. The half-life of a zero-order reaction is the time required for the concentration of the reactant to decrease to half of its initial value. Since the rate of reaction is constant, the time taken to decrease the concentration by half is also constant, regardless of the initial concentration. Therefore, this statement is correct.

b) Average life = 1.44 times half-life for a first-order reaction.
In a first-order reaction, the rate of reaction is directly proportional to the concentration of the reactant. The half-life of a first-order reaction is the time required for the concentration of the reactant to decrease to half of its initial value. The average life is the average time taken for the concentration of the reactant to decrease to 1/e (approximately 0.368) of its initial value. It can be mathematically proven that the average life is equal to 1.44 times the half-life for a first-order reaction. Therefore, this statement is correct.

c) Time of 75% reaction is thrice the half-life period in a second-order reaction.
In a second-order reaction, the rate of reaction is proportional to the square of the concentration of the reactant. The half-life of a second-order reaction is the time required for the concentration of the reactant to decrease to half of its initial value. However, the time required for the concentration to decrease to 75% of its initial value is not three times the half-life. It can be calculated using the integrated rate equation for a second-order reaction. Therefore, this statement is incorrect.

d) A 99.9% reaction, which is first order, takes place in 100 minutes if the rate constant of the reaction is 0.0693 min-1.
For a first-order reaction, the integrated rate equation is given by ln([A]t/[A]0) = -kt, where [A]t is the concentration at time t, [A]0 is the initial concentration, k is the rate constant, and t is the time. We can rearrange this equation to find the time required for a given percentage of reaction to occur.

For a 99.9% reaction, [A]t/[A]0 = 0.001. Substituting this value and the given rate constant into the integrated rate equation, we can solve for t.

ln(0.001) = -0.0693 * t

Solving for t, we find that t ≈ 100 minutes. Therefore, this statement is correct.

In summary, the correct statements about half-life period are:
- It is proportional to initial concentration for a zero-order reaction.
- Average life = 1.44 times half-life for a first-order reaction.
- A 99.9% reaction, which is first order, takes place in 100 minutes if the rate constant of the reaction is 0.0693 min-1.
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Which of the following statements are correct about half life period ?a)It is proportional to initial concentration for a zero order reaction.b)Average life = 1.44 times half life for a first order reaction.c)Time of 75% reaction is thrice of half life period in second order reaction.d)99.9% reaction which is first order, takes place in 100 minutes if the rate constant of the reaction is 0.0693 min-1.Correct answer is option 'A,B,C,D'. Can you explain this answer?
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Which of the following statements are correct about half life period ?a)It is proportional to initial concentration for a zero order reaction.b)Average life = 1.44 times half life for a first order reaction.c)Time of 75% reaction is thrice of half life period in second order reaction.d)99.9% reaction which is first order, takes place in 100 minutes if the rate constant of the reaction is 0.0693 min-1.Correct answer is option 'A,B,C,D'. Can you explain this answer? for JEE 2024 is part of JEE preparation. The Question and answers have been prepared according to the JEE exam syllabus. Information about Which of the following statements are correct about half life period ?a)It is proportional to initial concentration for a zero order reaction.b)Average life = 1.44 times half life for a first order reaction.c)Time of 75% reaction is thrice of half life period in second order reaction.d)99.9% reaction which is first order, takes place in 100 minutes if the rate constant of the reaction is 0.0693 min-1.Correct answer is option 'A,B,C,D'. Can you explain this answer? covers all topics & solutions for JEE 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Which of the following statements are correct about half life period ?a)It is proportional to initial concentration for a zero order reaction.b)Average life = 1.44 times half life for a first order reaction.c)Time of 75% reaction is thrice of half life period in second order reaction.d)99.9% reaction which is first order, takes place in 100 minutes if the rate constant of the reaction is 0.0693 min-1.Correct answer is option 'A,B,C,D'. Can you explain this answer?.
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