Answer:
(A.) H2 --> 2H+ 2 e- (oxidation)
Explanation:
A. oxidation is the removal of electron(s) from a substance. This is the case here, since AFTER the reaction you can see that there were electons "removed" from H2.
H2 --> 2H+ 2 e- (oxidation)
B. reduction is the addition of electron(s) to a substance
1/2 O2 + 2 e- + 2H+ --> H2O (reduction)
By the way:
Biochemical reactions often involve the transfer of complete hydrogen atoms, meaning an electron and a proton.
The substance oxidized (H2) is electron donor.
The substance reduced (O2) is electron acceptor.
Just remember this:
Prior to the reaction, the e donor is always reduced.
Prior to the reaction, the e acceptor is always oxidized.
