Question

balance the following equation
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Answer 1

There is an easy way to balance this reaction.

Find the change in oxidation state of Fe which is 3 - 2 = 1 and put it as the coefficient of Cr₂O₇²⁻

Similarly change in oxidation state of Cr ion is 6 - 3 = 3, but there are 2 Cr ions present. So, change in oxidation state in total for Cr = 2x3 = 6. Put 6 as the coefficient of Fe²⁺ and start balancing. You finally get..

6 Fe²⁺ + Cr₂O₇²⁻ + 14 H⁺  →  6 Fe³⁺ + 2 Cr³⁺ + 7 H₂O

Hope it helps!