I believe the answer is orbital hybridization theory
1. In first reaction reactant a is the electron donor, while b is the electron acceptor,
the oxidized product is c while the reduced product is d
2. in the second equation e is the electron donor, f is the electron acceptor
g is the oxidized product while h is the reduced product.
3. In the third reaction i is the electron donor, j is the electron acceptor , k is the oxidized product while l is the reduced product.
Occurs at a specific temperature
