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प्रश्न
Calculate the half-life of a first order reaction from the rate constant given below:
2 min−1
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उत्तर
For a first order reaction,
Half life (t1/2) = `0.693/k`
= `0.693/2`
= 0.346 min
संबंधित प्रश्न
The rate constant for a first order reaction is 100 s–1. The time required for completion of 50% of reaction is _______.
(A) 0.0693 milliseconds
(B) 0.693 milliseconds
(C) 6.93 milliseconds
(D) 69.3 milliseconds
A first order reaction takes 30 minutes for 50% completion. Calculate the time required for 90% completion of this reaction.
(log 2 = 0.3010)
The half-life for radioactive decay of 14C is 5730 years. An archaeological artifact containing wood had only 80% of the 14C found in a living tree. Estimate the age of the sample.
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The rate constant for the first order decomposition of H2O2 is given by the following equation:
log k = 14.34 − 1.25 × 104 K/T.
Calculate Ea for this reaction and at what temperature will its half-period be 256 minutes?
The unit of rate constant for zero order reaction is _______.
(A) t–1
(B) mol dm–3 t–1
(C) mol–1 dm3 t–1
(D) mol–2 dm6 t–1
A first order reaction takes 10 minutes for 25% decomposition. Calculate t1/2 for the reaction.
(Given : log 2 = 0.3010, log 3 = 0.4771, log 4 = 0.6021)
Show that the time required for 99% completion is double of the time required for the completion of 90% reaction.
The half life period of a first order reaction is 6. 0 h . Calculate the rate constant
After 2 hours, a radioactive substance becomes `(1/16)^"th"` of original amount. Then the half life ( in min) is
Define half life of a reaction.
Show that for a first order reaction half life is independent of initial concentration.
The half-life of cobalt 60 is 5.26 years. The percentage activity remaining after 4 years is ______%.
The amount of C-14 isotope in a piece of wood is found to be 1/16th of its amount present in a fresh piece of wood. The age of wood, half-life period of C-14 is 5770 years, is ______ years.
For the given first order reaction A → B the half life of the reaction is 0.3010 min. The ratio of the initial concentration of reactant to the concentration of reactant at time 2.0 min will be equal to ______. (Nearest integer)
A reaction has a half-life of 1 min. The time required for 99.9% completion of the reaction is ______ min.
(Round off to the nearest integer).
[Use: In 2 = 0.69; In 10 = 2.3]
Assertion (A): The half-life of a reaction is the time in which the concentration of the reactant is reduced to one-half of its initial concentration.
Reason (R): In first-order kinetics, when the concentration of reactant is doubled, its half-life is doubled.
The unit of rate constant of zero order reaction is ______.
