Question

The rate constant of a first order reaction is doubled when the temperature is increased from ${20}^{o}C$ to ${25}^{o}C$. How many times the rate constant will increase if the temperature is raised from ${20}^{o}C$ to ${40}^{o}C$?

• A. $4$
• B. $8$
• C. $16$
• D. $32$
• E. $64$

Answer 1

The correct option is C $16$

For every $5^o$ rise in temperature, the rate constant becomes double.
$\therefore$ For ${20}^{o}C$ ($5\times 4$ times) rise in temperature, the rate constant, $k=2^4=16$.