Consider the redox reaction below.

Upper Z n (s) plus 2 upper H upper C l (a q) right arrow upper Z n upper C l subscript 2 (a q) plus upper H subscript 2 (g 0).

Which half reaction correctly describes the oxidation that is taking place?
Upper Z n superscript 2 plus (s) plus 2 e superscript minus (a q) right arrow upper Z n (s).
Upper Z n (s) right arrow upper Z n superscript 2 plus (a q) plus 2 e superscript minus.
2 upper H superscript plus, plus 2 e superscript minus right arrow upper H subscript 2.
Upper H subscript 2 plus 2 e superscript minus right arrow 2 upper H superscript plus.