(i) What is an elementary reaction ? Give the differences between order and molecularity of a reaction.
(ii) In a first order reaction A `to` products, 60% of the given sample of A decomposes in 40 min. what is the half life of the reaction ?

Explanation

(i) Elementary reaction: Each and every single step in a reaction mechanism is called an elementary reaction.
Differences between order and molecularity :

(ii) Sol. `k=(2.303)/(t)log""(a)/(a-x)`
`k=(2.303)/(40" min")log""(100)/((100-60))iff k=(2.303)/(40)log((100)/(40))`
`k=0.0575(0.3979)iff k=0.02287" min"^(-1)`
`t_((1)/(2))=30.31" min"`.