A first order reaction takes 20 minutes for 25% decomposition. Calculate the time when 75% of the reaction will be completed.
(Given, `log2=0.3010,log3=0.4771,log4=0.6021`)

Answer

`96.3" min"`

Explanation

Proceed as in Solved Problem 3.
`k=(2.303)/(20)log""(a)/(a-0.25a)=(2.303)/(20)log""(4)/(3)=0.0144" min"^(-1)`
`t=(2.303)/(k)log""(a)/(a-0.75a)=(2.303)/(0.0144)log4=96.3" min"`