The isomerization of cyclopropane (CP) to propene (P) is a first order process. At 760 K, 15% of a sample of cyclopropane changes to propene in 6.8 minutes. What is the half- life of cyclopropane at 760 K

The half life of cyclopropane at 760 K is 28.99 minutes.

Explanation:

Rate law expression for first order kinetics is given by the equation:

where,

k = rate constant  = ?

t = time taken for decay process = 6.8 minutes

= initial amount of the sample = 100 grams

[A] = amount left after decay process =  (100 - 15) = 85 grams

Putting values in above equation, we get:

The equation used to calculate rate constant from given half life for first order kinetics:

where,

= half life of the reaction = ?

k = rate constant of the reaction =

Putting values in above equation, we get:

Hence, the half life of cyclopropane at 760 K is 28.99 minutes.

a is the correct answer