All Courses
Explore Courses UPSC Exam UPSC Test Series Free Notes EduRev Infinity Get the App Login Join for Free
Sign in Open App
JEE Exam  >  JEE Questions  >  Which of the following statements are correct... Start Learning for Free
SaveJoin the Discussion on the App
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?
FREE This question is part of
Download PDF Attempt Test
Download PDF Attempt this Test
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
View all questions of this test
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.
< Previous Question Next Question >
Explore Courses for JEE exam

Similar JEE Doubts

There are many reactions which obey a first order rate equation although it reality they are bi- or ter-molecular. As an example of these may be taken the decomposition of Carbonyl sulfide in water, namely, COS + H20 002 + H2SAccording to the law of mass action this reaction should be second order with the rate dependent on the concentration of both the carbonyl sulfide and the water. Actually however, the rate is found to be first order with respect to the carbonyl sulfide and independent of the water Reactions exhibiting such behaviour are said to be pseudo-molecular.The pseudo-unimoecuar nature of this reaction is explainable by the fact that water is present in such excess that its concentration remains practically constant during the course of the reaction. Under these condition b x = b, and the rate equation becomesOn integration this leads towhich is the equation for a first order reaction. It is evident, however, that the now constant k is not independent of the concentration, as is the case with true first order constants, but may vary with b if the latter is changed appreciably, When such is the case, the true constant k2 can be obtained from k by dividing the latter by b. pseudo-molecular reactions are encountered whenever one or more of the reactants remain constants during the course of an experiment. This is the case with reactions conducted in solvents which are themselves one of the reactants, as in the decomposition of carbonyl sulfide in water, or in the esterification of acetic anhydride in alcohol(CH3C0)20 + 2C2H5OH 2CH3C00C2H5 + H20Again, this is also true of reactions subject to catalysis, in which case the concentration of the catalyst does not change. The decomposition of diacetone alcohol to acetone in aqueous solution is catalysed by hydroxyl ions, with the rate proportional to the concentration of the alcohol and that of the base. Since the concentration of the base does not change within any one experiment, however, the rate equation reduces to one of first order with respect to the alcohol. But the rateconstant k obtained for various concentrations of base are not identical, as may be seen from table. To obtain from these the true second order velocity constant, the ks must be divided by the hydroxyl ion concentration. When this is done excellent k2 values result, as column 3 indicatesTable : Decomposition of diacetone alcohol in water at 25C (Catalyst : NaOH)Q.By what factor does the rate of reaction of diacetone alcohol in water solution change if p0H is increased by 2 units other things remaining same ?

Not all chemical reactions proceed to a stage at which the concentrations of the reactants become vanishingly small. Here we consider the kinetics of such reactions.Let a reaction be represented in general terms by the schemewhere k., and k_., represent the rate constants for the forwards and reverse reactions, respectively. The equilibrium constant for this reaction may be written asK = [B] /[A] = K1/K1 --(1)where the subscript 00 refers to a time t, sufficiently long to establish equilibrium at the given temperature. The initial concentration of species A is [A]O, and that of B is [B]O . After a time t, let the concentration of species A be [A/t and that of B be [Bat. The total rate of change of [At is given byd[A]t/dt= - K1[A]t + k-1[B]tIf, as is usual, [B]O is initially zero, it follows from a mass balance that at any time t,[Bat = [A]0 - [A]t, whenced[A]t/dt = K1[A]t + k-1([A]O - [A]t)ord[A]t/dt = (K1 + k-1)For the reaction (having both 1ts order reactions), the concentration as a function of time are given for a certain experimental run along with a tangent to the graph at the origin. The ratio of the magnitude of the slopes of the graph of [A/ and [C/ at the origin would be

The rate of chemical reaction at a particular temperature is proportional to the product of the molar concentration of reactants with each concentration term raised to the power equal to the number of molecules of the respective reactant taking part in the reaction. aA + bB products, rate of reaction a [Aka [Bib = k [Aka [Bib, where k is the rate constant of the reaction.EQUILIBRIUM CONSTANT (k) For a general reaction aA + bB = cC + dD, forward rate rf = kf [A]a [B]b, backward rate rb = kb [Cicpyi ,concentrations of reactants products at equilibrium are related bywhere all theconcentrations are expressed in mole/liter.In the expression of equilibrium constant those components are kept whose concentration changes with time.If equilibrium is estabilished by taking all the components in the reaction then to predict the direction of reactions we calculate the reaction quotient (Q).The values of expression at any time during reaction is called reaction quotient if Q Kc reaction proceed in backward direction until equilibrium in reached if Q Kc reaction will proceed in forward direction until equilibrium is established if Q = KC Reaction is at equilibriumQ.Initial concentration of A is twice the initial concentration of `B. At equilibrium concentration of A and a are same then equilibrium constant for the reaction is

Top Courses for JEEView all

Top Courses for JEE

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?
Question Description
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?.
Solutions 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? in English & in Hindi are available as part of our courses for JEE. Download more important topics, notes, lectures and mock test series for JEE Exam by signing up for free.
Here you can find the meaning of 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? defined & explained in the simplest way possible. Besides giving the explanation of 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?, a detailed solution 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? has been provided alongside types of 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? theory, EduRev gives you an ample number of questions to practice 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? tests, examples and also practice JEE tests.
Explore Courses for JEE exam

Top Courses for JEE

Explore Courses

Suggested Free Tests

Signup for Free!
Signup to see your scores go up within 7 days! Learn & Practice with 1000+ FREE Notes, Videos & Tests.
10M+ students study on EduRev
Get App
© EduRev
Education Revolution
Signup to see your scores go up within 7 days!
Access 1000+ FREE Docs, Videos and Tests
Takes less than 10 seconds to signup