The thermal decomposition of compound is of first order. If `50%` of a sample of the compound is decomposition in `120 min` how long will it take for `90%` of the compound to decompose?

Explanation

Given: `t_(50%)=120` minute
`K=2.303/t "log" N_(0)/N`
for `50 %` decay `K=2.303/120 "log" N_(0)/(N_(0)//2)`
`( :' N=N_(0)//2) …(i)`
for `90%` decay `K=2.303/t log N_(0)/(N_(0)//10)`
`( :' N=N_(0)//10) …(ii)`
`t=398.78 minute`