Question

A first order reaction has a specific reaction rate of 10-² sec-¹.How much time will it take for 20 g of the reactant to reduce to 5 g?
a) 138.6 sec
b) 346.5 sec
c) 693.0 sec
d) 238.6 sec​

Answer 1

Answer:

a. option is the correct answer

Answer 2

Answer:

Option (a) is correct

Explanation:

For a first order reaction,

k = 2.303 ÷ t log [ A]0 ÷ [A]t

10-² = 2.303 ÷ t log 20 ÷ 5

10-² = {2.303 × 0.6020 }÷ t

t = 138.6 sec

Hope it will help you.Thanks.