NAD+ and NADH + H+

supposed to find out whY is it that we write the bioChem eqn as

NAD⁺ + 2H --> NADH + H⁺

there are books that write the product as

NADH₂

this was what i was so nervous about.. cos i can't seem to find the answer!!! it is either i find the correct answer, or get kicked out of class.. smart huh? i got an extra tip yesterday though.. it is something to do with the structure..

this is how it looks like, i've gathered.. (just google it 4GS) and i have noticed the difference in the aromatic ring before and after the reduction process..and of course the addition of the H to the ring.. now.. the problem is.. how do i explain that????

i'm going back to Chem.. my worst subject.. *faint* (still prefer this to Phy.. which is practically gone case for me.. lol~)

and now, i've just noticed another thing.. why must we add 2H? was that from the water molecule?? or?? *aih.. incriminating myself.. zd*