Question

Page
5
show that in a first corder reaction time a
required for completion of 90%
is 10 times of half life (+1/2) of the
reation.​

Answer 1

Half life is the amount of time taken by a radioactive material to decay to half of its original value. Thus it is proved that time take for completion of 99.9% for reaction is 10 times of that of half life

Answer 2

Explanation:

100-------->50------>25-------->12.5

upto here , 87.5 % reaction is complete by leaving 12.5% of reactants,in 3 half lives.

Now,

to reach 90% it takes a fraction of half life.

So, total half lives are around 3.3 times.

in 10 half lives, it will be completed around 99.9% of reaction.