The rate constant for a first order reaction is 4.606 × 10-3 s-1. The time required to reduce 2.0 g of the reactant to 0.2 g is :

Question

The rate constant for a first order reaction is 4.606 × 10-3 s-1. The time required to reduce 2.0 g of the reactant to 0.2 g is : (A) 100 s (B) 200 s (C) 500 s (D) 1000 s

Tardigrade Admin · Accepted Answer

K=(2.303/t)log (a/a-x) t=(2.303/4.606× 10-3) log (2/0.2) =(1000/2) log 10 =500 sec (as log 10=1)

Q. The rate constant for a first order reaction is $4.606 \times 1 0^{- 3} s^{- 1}$ . The time required to reduce $2.0 g$ of the reactant to $0.2 g$ is :

100 s

200 s

500 s

1000 s

$K = \frac{2.303}{t} l o g \frac{a}{a - x}$
$t = \frac{2.303}{4.606 \times 1 0 ^{- 3}}$
$l o g \frac{2}{0.2}$
$= \frac{1000}{2} lo g 10$
$= 500 sec$
(as log $10 = 1)$

Q. The rate constant for a first order reaction is 4.606×10−3s−1. The time required to reduce 2.0g of the reactant to 0.2g is :