RULE OF THUMB RATE
According to the rule of Thumb Rate:
“Rate constant of a reaction increases of factor of 2 for each 10 ºC or 10K rise in temperature, although the actual amount of increase differs from one reaction to another”.
The reasons for the increase in rate constant are:
(a) As temperature increases the velocity of molecules also increases, this results in the increase of frequency of collisions.
(b) The rise in temperature raises the kinetic energy of each molecule. The fraction of molecules possessing Threshold or Activation energy becomes double, as a result number of effective collisions is also doubled, and hence rate and rate constant are doubled.