Question

It takes 32 minutes to complete 99% of a first order reaction from start. Calculate the time required (in a minute) to complete 99.9% of the reaction from the start?

• A. 50
• B. 48
• C. 55
• D. 46

Answer 1

The correct option is B 48

It takes 32 minutes to complete 99% of a first order reaction.
$K=\frac{1}{32}ln\frac{a}{0.01a}=\frac{ln100}{32}$
$t=\frac{32}{ln100}ln\frac{a}{0.01a}$
$t=48min$