Question

The half-life period of a first order reaction is 100
minute. Calculate the time required for the reaction
to be completed by 90%.​

Answer 1

Step-by-step explanation:

Half life time (

2

t

1

)= 100 sec. (given)

K=

100

0.693

Time required for 90% completion?

Here let initial concentration =a

Concentration decomposed is 90%

x=

100

90×a

=0.9a

Now,

t=

t

1

/2

0.693

2.303

log

a−x

a

⇒

100

2.303

log

a−0.9a

a

⇒

0.693

2.303

log

0.1a

a

⇒

100

2.303

log10

⇒

0.693

2.303

×100×log10

⇒339.32sec

Approx. 333 seconds