A $\to$ B
at Very Low Pressures Many Such Reactions Occur by Occur

Essay

A $\to$ B
At very low pressures many such reactions occur by the following mechanism:

(A* represents a molecule with sufficient energy to overcome the activation energy barrier. )
a.Which of the three reactions above is/are elementary?
b.Where appropriate,identify the molecularity of the reactions.
c.Show that the proposed mechanism is consistent with reaction 1,the observed reaction.
d.Given the mechanism above,suggest a likely rate law for reaction (1).