Which reactions are oxidation-reduction reactions? Check all that apply.

2 upper N a plus upper C l subscript 2 right arrow 2 upper N a upper C l.

Upper P b (upper O upper H) subscript 2 right arrow upper P b upper O plus upper H subscript 2 upper O.

Upper C u plus 2 upper A g upper N upper O subscript 3 right arrow upper C u (upper N upper O subscript 3)subscript 2 plus 2 upper A g.

Upper Z n upper B r subscript 2 plus 2 upper A g upper N upper O subscript 3 right arrow 2 upper A g upper B r plus upper Z n (upper N upper O subscript 3) subscript 2.

Upper C upper H subscript 4 plus 2 upper O subscript 2 right arrow upper C upper O subscript 2 plus upper H subscript 2 upper O.