मराठी

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.

Advertisements
Advertisements

प्रश्न

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.

पर्याय

  • Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).

  • Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of Assertion (A).

  • Assertion (A) is true, but Reason (R) is false.

  • Assertion (A) is false, but Reason (R) is true.

MCQ
Advertisements

उत्तर

Assertion (A) is true, but Reason (R) is false.

Explanation:

The half-life of a first-order reaction is independent of the initial concentration.

shaalaa.com
  या प्रश्नात किंवा उत्तरात काही त्रुटी आहे का?
2022-2023 (March) Delhi Set 2

व्हिडिओ ट्यूटोरियलVIEW ALL [1]

संबंधित प्रश्‍न

 A first order reaction takes 40 minutes for 30% decomposition. Calculate t1/2 for this reaction. (Given log 1.428 = 0.1548)


Calculate the half-life of a first order reaction from the rate constant given below:

200 s−1


The experimental data for decomposition of N2O5

\[\ce{2N2O5 -> 4NO2 + O2}\]

in gas phase at 318 K are given below:

t/s 0 400 800 1200 1600 2000 2400 2800 3200
102 × [N2O5]/mol L−1 1.63 1.36 1.14 0.93 0.78 0.64 0.53 0.43 0.35
  1. Plot [N2O5] against t.
  2. Find the half-life period for the reaction.
  3. Draw a graph between log [N2O5] and t.
  4. What is the rate law?
  5. Calculate the rate constant.
  6. Calculate the half-life period from k and compare it with (ii).

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


In a first-order reaction A → product, 80% of the given sample of compound decomposes in 40 min. What is the half-life period of the reaction? 


After 2 hours, a radioactive substance becomes `(1/16)^"th"` of original amount. Then the half life ( in min) is


A first-order reaction takes 69.3 min for 50% completion. What is the time needed for 80% of the reaction to get completed? (Given: log 5 = 0.6990, log 8 = 0.9030, log 2 = 0.3010)


Observe the graph shown in figure and answer the following questions:


Write the relationship between k and t1/2 (half-life period)


A sample of U238 (half-life = 4.5 × 109 years) ore is found to contain 23.8 g of U238 and 20.6 g of Pb206. The age of the ore is ______ × 109 years.


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.


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×