Write a balanced half-reaction for the reduction of dichromate ion cr2o-27 to chromium ion cr 3 in basic aqueous solution. be sure to add physical state symbols where appropriate.

Question

Ray Gentry

Chemistry

27 May, 23:28

Write a balanced half-reaction for the reduction of dichromate ion cr2o-27 to chromium ion cr 3 in basic aqueous solution. be sure to add physical state symbols where appropriate.

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Zaid Young · Answer 1

Half reaction: Cr₂O₇²⁻ (aq) + 7H₂O (l) + 6e⁻ → 2Cr³⁺ (aq) + 14OH⁻ (aq).

Chromium change oxidation number from + 6 in dichromate ion Cr₂O₇²⁻ to + 3 in chromium cation.

Sum of the charges on the left side of the half reaction is - 2 and on the left side is - 8 (2· (+3) + 14· (-1)), so six electrons must be added on the left side of half reaction.