Question

A first order reaction is 20% completed in 40 minutes. Calculate half life period of the reaction

Answer 1

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Answer 2

Answer:

Let initial conc. of reactant (a)100,t=40 minutes.

90% reaction gets completed in 40 minutes i.e.,

x=90

k=

t

2.303

log

a−x

a

=

40

2.303

log

100−90

100

=

40

2.303

log10

=

40

2.303

×1=5.757×10

−2

min

−1

.

But t

1/2

=

k

0.693

t

1/2

=

5.757×10

−2

0.693

=10.3min