In a hydrocarbon solution, the gold compound (CH3)3AuPH3 decomposes into ethane (C2H6) and a different gold compound, (CH3)AuPH3. The following mechanism has been proposed for the decomposition of (CH3)3AuPH3:
Step 1:

(fast)
Step 2:

(slow)
Step 3:

(fast)
(a) What is the overall reaction?
(b) What are the intermediates in the mechanism?
(c) What is the molecularity of each of the elementary steps?
(d) What is the rate-determining step?
(e) What is the rate law predicted by this mechanism?
(f) What would be the effect on the reaction rate of adding PH3 to the solution of (CH3)3AuPH3?