Q16 of 39 Page 117

The rate constant for a first order reaction is 60 s–1. How much time will it take to reduce the initial concentration of the reactant to its 1/16th value?

Given:


Order of the reaction = 1


Let, Initial concentration [R]°= x


Final concentration [R] = x/16


Rate constant k = 60 s-1


We know, time



⇒


⇒


Solving, we get t = 4.6 × 10-2s


More from this chapter

All 39 →
14

The half-life for radioactive decay of 14C is 5730 years. An archeological artifact containing wood had only 80%of the 14C found in a living tree. Estimate the age of the sample.

 15

The experiemental data for decomposition of N2O5

[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



(i) plot N2O5 against t


(ii) Find the half-life period for the Reaction.


(iii) Draw a graph between log[N2O5]and t.


(iv) what is the rate law?


(v) Calculate the rate constant.


(vi) Calculate the half-life period from k and compare it with (ii)

 17

During nuclear explosion, one of the products is 90Sr with half-life of 28.1 years. If 1μg of 90Sr was absorbed in the bones of a newly born baby instead of calcium, how much of it will remain after 10 years and 60 years if it is not lost metabolically.

 18

For a first order reaction, show that time required for 99% completion is twice the time required for the completion of 90% of reaction.