Acompound decomposes by a first-order process. if 26 of the compound decomposes in 60 minutes, the half-life of the compound is .

(a) 26
(b) 31
(c) 18
(d) 5
(e) 138

(E) 138

Explanation:

Using integrated rate law for first order kinetics as:

Where,  

is the concentration at time t

is the initial concentration

Given:

26 % is decomposed which means that 0.26 of is decomposed. So,

= 1 - 0.26 = 0.74

t = 60 min

Taking natural log both sides, we get that:-

k = 0.005018 min⁻¹

Also,  Half life expression for first order:-

Where, k is rate constant

So,  

The correct option is:- (E) 138

the answer is b because, investigating whether another species of moth also drinks tears might be interesting, but it would not directly explain why this species of moth does.

to explain why this species of moth drinks tears, the scientist could ask: "what nutrients that moths need are in elephant tears? "

the scientist could experiment with moth repellent or oter ways to keep the moths away, but that would not answer his original question.