The rate of a first order reaction is 0.04 mol l-1 s-1 at 10 seconds and 0.03 mol l-1 s-1 at 20 seconds after initiation of the reaction. The half-life period of the reaction is :

Question

The rate of a first order reaction is 0.04 mol l-1 s-1 at 10 seconds and 0.03 mol l-1 s-1 at 20 seconds after initiation of the reaction. The half-life period of the reaction is : (A) 34.1 s (B) 44.1 s (C) 54.1 s (D) 24.1 s

Tardigrade Admin · Accepted Answer

K = (2.303/10) log (0.04/0.03) K = (2.303/10) log (4/3) K = (2.303 ×0.123/10) K = 0.0285 t1/2 = (0.693/K) t1/2 = (0.693/0.0285) = 24.1s.

Q. The rate of a first order reaction is $0.04 m o l l^{- 1} s^{- 1}$ at 10 seconds and $0.03 m o l l^{- 1} s^{- 1}$ at 20 seconds after initiation of the reaction. The half-life period of the reaction is :

34.1 s

44.1 s

54.1 s

24.1 s

$K = \frac{2.303}{10} lo g \frac{0.04}{0.03}$
$K = \frac{2.303}{10} lo g \frac{4}{3}$
$K = \frac{2.303 \times 0.123}{10}$
$K = 0.0285 t_{1/2} = \frac{0.693}{K}$
$t_{1/2} = \frac{0.693}{0.0285} = 24.1 s .$

Q. The rate of a first order reaction is 0.04moll−1s−1 at 10 seconds and 0.03moll−1s−1 at 20 seconds after initiation of the reaction. The half-life period of the reaction is :