1. What kind of metal centers favor reductive elimination?

Electron deficient high valent metal centers.

2. Complete the sentence correctly.

(a)  Oxidative addition is frequently observed in coordinatively saturated/unsaturated metal complexes. 
(b)  Oxidative addition is accompanied by increase/decrease in the oxidation state of the metal. 
(c)  Reductive elimination is accompanied by increase/decrease in the coordination number of the metal. 

(a) Unsaturated.
(b) Increase in the oxidation state by two units.
(c) Decrease in the coordination numbers by two units.

3. How does the geometry of the square planar complexes change upon oxidative addition reactions?

Square planar to octahedral.

4. Complete the reaction.