The thermal decomposition of formic acid (HCOOH) is a first order reaction with the rate constant of `2.4 xx 10^(-3)s^(-1)` at a certain temperature.Calculate how long will it take for three-fourth of initial quantity of HCOOH to decompose.

Answer

`9" min "38" s"`

Explanation

`x=(3)/(4)a,t=(2.303)/(k)log""(a)/(a-3//4a)=(2.303)/(2.4xx10^(-3))log4s=(2.303)/(2.4xx10^(-3))(0.6021)s=9" min "38" s"`
or `t_(1//2)=(0.693)/(k)=(0.693)/(24xx10^(-3))s=288.75s,t_(3//4)=2xxt_(1//2)`