The half life of a first order reaction
- A. doubles as the reaction proceeds
- B. depends on the initial concentration
- C. is constant and independent of the initial concentration
- D. is always one second
Explanation
For first order kinetics the time taken for the concentration to fall by half is fixed, so successive halvings take equal times, and this is precisely why radioactive decay is described by a half life. The relationship is half life equals 0.693 divided by k. For zero and second order reactions the half life does depend on the starting concentration.