Question

A first order reaction takes 40 min for 75% decomposition. Calculate rate constant.

[Given: log 2 = 0.30, log 4 = 0.60]

Answer 1

According to the first-order reaction

`t = 2.303/k log  10/(100 - x)`

`k = 2.303/(40 min) log  100/(100 - 75)`

`k = 2.303/(40 min) log  100/25`

`k = 2.303/(40 min) log4`

`k = 2.303/(40 min) xx 0.60`

k = 0.0345 min⁻¹