Question

At 300 K, a certain I order reaction is 50% completed in 20 minutes. At 350 K, the same reaction is completed in 5 minutes. The ratio of the rate constant at 350 K and 300 K is:

Answer 1

At 300 K, a certain I order reaction is 50% completed in 20 minute.
At 350 K, the same reaction is 50% completed in 5 minutes.
The ratio of the half life periods is $\frac{5min}{20min}=\frac{1}{4}$
The ratio of the rate constants is the reciprocal of the ratio of the half lives.
The ratio of rate constant at 350 K and 300 K is $\frac{1}{\frac{1}{4}}=4$