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Chemical Kinetics I 127
give an intermediate cation. The final step of the reaction is the loss
of the proton to give the a-brominated product. The proton is
regenerated at the end of the reaction, and therefore is catalytic. The
enolic equilibrium concentration in propanone at 298 K is only
0.0025%. The conversion of the ketone to the enol intermediate is
the rate-determining step, or slow step of the reaction, since the
subsequent bromination of the double bond is quite rapid. The
existence of the enol intermediate and the mechanism of the reaction
was first proposed, on the basis of the unique kinetic experimental
results.

SUMMARY
In Chapter 8, the basic laws of kinetics have been introduced,
including both zero-order and first-order reactions. A similar analysis
can be proposed for second-order reactions, where the integration is
slightly more difficult. In the final chapter of this text, Chapter 9, the
Arrhenius Equation and a general working method to solve graphical
problems will be introduced.