For a first order reaction, the initial concentration of a reactant is 0.05 M. After 45 min it is decreased by 0.015 M. Calculate halfreaction time. (t1/2)

Question

For a first order reaction, the initial concentration of a reactant is 0.05 M. After 45 min it is decreased by 0.015 M. Calculate halfreaction time. (t1/2) (A) 87.42 min (B) 25.90 min (C) 78.72 min (D) 77.20 min

Tardigrade Admin · Accepted Answer

k = (2.303/45) log (0.05/0.035) k = (2.303/45) × 0.1523 =0.00779 t1/2 = (0.693/0.00779) = 88.96 min

Q. For a first order reaction, the initial concentration of a reactant is 0.05 M. After 45 min it is decreased by 0.015 M. Calculate halfreaction time. $(t_{1/2})$

87.42 min

25.90 min

78.72 min

77.20 min

$k = \frac{2.303}{45} l o g \frac{0.05}{0.035}$
$k = \frac{2.303}{45} \times 0.1523 = 0.00779$
$t_{1/2} = \frac{0.693}{0.00779} = 88.96 min$

Q. For a first order reaction, the initial concentration of a reactant is 0.05 M. After 45 min it is decreased by 0.015 M. Calculate halfreaction time. (t1/2​)