Please help! Half reaction problem.

Question

I need help figuring these two half reaction problems out:?
My professors explanation made no sense to me so im hoping someone can help me out. These are the two half reactions:
Oxaloacetate+2H++2e-=malate
Fumarate+2H++2e-=succinate
1. Which of the oxidizing agents is stronger?
(Professor said fumarate)
2.which of the reducing agents is stronger?
(Malate)
3. What is the full reaction?
(Have no idea)
4. Which two agents will be present in highest concentration?
(Succinate and oxaloacetate?

Answer 1

You cant tell which oxidizing or reducing agent is stronger without additional information aboutvtge reduction or oxidation potentials. If fumarate is the stronger oxidizing agent then it will be redced and malate will be oxidized. The half reactions will be

Fumarate + 2e ==> succinate

oxaloacetate ==> malate + 2e-

Full rx is

fumarate + oxaloacetate ==> succinate + malate