why not lui beve un vino al acido?

I could be wrong, but doesn't 'vino acido' also mean vinegar?

do "agro" and "acido signify the same?

"vino agro" is given as wrong. Is it wrong?

Google translate says vinegar is aceto

I thought we just learned that aspro is sour, acido I thought was acidic?

Al would mean 'with' here, that's not correct - wine with sour :)

can amaro be used instead of acido?

Why not "lui beve un acido vino"?

The right translation for sour in this case would be 'amaro' ...

amaro means bitter