We will look at three other examples of reaction mechanisms, and see how they account for the observed rate expressions.
The Hydrogen-Iodine Reaction
An example of a long-standing error in reaction
mechanisms, which we and others have used so often because it apparently
is so well-behaved. The reaction is
 |
and the observed rate equation is
 |
For nearly seventy-five years, everyone assumed that the process occurred by the collision of one hydrogen molecule and one iodine molecule, with enough energy to bring about reaction.
Only as recently as 1967 was it demonstrated that the actual reaction involves the reversible dissociation of I2 molecules into atoms, followed by the reaction of these I atoms with H2 : |
|
|
 |
