Which anion can undergo both oxidation and reduction?

CHEMISTRY · Single correct · A Level · Chemistry · Oxidation, reduction and redox reactions · Oxidation, reduction and redox reactions

Problem

Which anion can undergo both oxidation and reduction? (1)

\text{Cr}_2\text{O}_7^{2-}

(2)

\text{NO}_3^-

(3)

\text{OCl}^-

(4)

\text{S}^{2-}