Question

Malathion, an organophosphate parasympathomimetic, is an insecticide of relatively low human toxicity. It has been widely used in aerial spray to combat fruit fly and West Nile virus. The photodegradation of this insecticide can be described by first-order reaction with a half-life of 15 hr under sunlight. If a tank of malathion solution was exposed to sunlight from 8:00 am to 2:00 pm on a spray day, what is (a) the first-order rate constant in hr, and (b) the percentage of malathion remained from its original strength? Malathion, an organophosphate parasympathomimetic, is an insecticide of relatively low human toxicity. It has been widely used in aerial spray to combat fruit fly and West Nile virus. The photodegradation of this insecticide can be described by first-order reaction with a half-life of 15 hr under sunlight. If a tank of malathion solution was exposed to sunlight from 8:00 am to 2:00 pm on a spray day, what is (a) the first-order rate constant in hr, and (b) the percentage of malathion remained from its original strength?

Answer 1

Solution:

Given that
a) Rate Constant Ck) c. For Rrst bidy Cackion) k.693 s, uina Airst order equation Aloo In (loo) : 0.0462 x 6 Nou okirg An hi .3193 loo 1. 319u3 At、 36.79 maincd 75 19