Question

first order reaction is 10​

Answer 1

Your full question-

A first order reaction is 10% complete in 20 min. The time taken for 19% completion is:

Answer-

For first order reaction:

Initially reaction is 10% complete, $$x=10;\ t=20 $$min

t=\dfrac{2.303}{k} log\dfrac{a}{a-x}t=

k

2.303

log

a−x

a

let a=100a=100

20 =\dfrac{2.303}{k} log\dfrac{100}{100-10}20=

k

2.303

log

100−10

100

20 =\dfrac{2.303}{k} \times 0.045320=

k

2.303

×0.0453

k = 0.1151 \times 0.0453 = 0.00521k=0.1151×0.0453=0.00521

Substituting the value of kk and x = 19x=19

t = \dfrac{2.303}{0.00521} log \dfrac{100}{100-19}t=

0.00521

2.303

log

100−19

100

t= 442.034 \times 0.09131 = 40.3 mint=442.034×0.09131=40.3min