When Cr dissolves in 1 M H₂Cr₂O₇
Cr(s) ⇄ Cr³⁺ + 3 e⁻
Cr₂O₇²⁻ + 14 H⁺ + 6 e⁻ ⇄ 2 Cr³⁺ + 7 H₂O
by multiplying the first equation by 2 and add the 2 equations;
The balanced redox reaction will be:
2 Cr(s) + Cr₂O₇²⁻(aq) + 14 H⁺(aq) → 4 Cr³⁺(aq) + 7 H₂O(l)
