- JEE Main 2018:
A first order reaction is 50% completed in 30 minutes. Calculate the time required for 90% completion of the reaction.
Solution:
The formula for the time taken for the completion of a first order reaction is:
t = (2.303)/(k) log([A]0/[A])
Where,
- t is the time taken for the completion of the reaction
- k is the rate constant of the reaction
- [A]0 is the initial concentration of the reactant
- [A] is the concentration of the reactant at time t
In this case, the initial concentration of the reactant is [A]0 = 100% and the concentration of the reactant at 50% completion is [A] = 50%. So, we can substitute these values into the equation to find the rate constant:
t = (2.303)/(k) log(100/50)
t = (2.303)/(k) log(2)
