The rate constant of a first order reaction is `15 xx 10^(-3) s^(-1)`. How long will 5.0g of this reactant take to the reduce to 3.0 g?

Explanation

Applying first order kinetic equation,
`t = (2.303)/(k) log.(a)/((a-x))`
`k = 5 xx 10^(-3) s^(-1), a = 5 g, (a-x) = 3 g`
`t = (2.303)/(5 xx 10^(-3)) log.(5)/(3) = 34.07 s`