WAEC - Chemistry (2002 - No. 3)

Consider the following equation; Cr₂O_7(aq)^2- + 14H⁺_(aq) + 6e^- → 2Cr³⁺_(aq) + 7H₂O_(I). The oxidation number of chromium changes from

-2 to + 3

- 2 to + 6