Question

(b) A First order reaction takes 40 minutes for 30% completion. Calculate
its half life period. (log 7=0.845)​

Answer 1

Answer:

A first order reaction takes 40 minutes for 30% decomposition calculate t1 2

A first order reaction takes 40 minutes for 30% decomposition. Calculate t1/2 value (log 7 = 0.845) .

Answer 2

Answer:

77.7 mins

Explanation:

Let a be the initial concentration. After 40 minutes, the concentration is 0.7a

[$a-\frac{30}{100} a$]=0.7a

$t_{1/2} = \frac{0.6932}{k}$

since the value of k is not given, we need to find it.

$k= \frac{2.303}{t} log\frac{A_0}{A_0-x}$

substituting the values,

k= 2.303/40 log A/0.7A

k= $8.92*10^-^2 /min$

t1/2= 0.6932/8.92*10^-2

$t_1_2= 77.7 min$

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