3. Examine the reaction mechanism found below:

Step 1: P₂+Q₂ → 2PQ (slow)

Step 2: 2PQ→→ P₂Q₂ (fast)

Step 3: P₂Q₂ →→ P₂ + Z (very fast)

a. Draw a circle around any reaction intermediates.

b. Draw a box around any species that can be considered a catalyst.

c. In the box above, provide the overall equation for this process.

d. In the box below, provide the rate law based on this mechanism.