Answer:
Cr
2
O
7
2−
+14H
+
+6Fe
2+
→2Cr
3+
+6Fe
3+
+7H
2
O
During the reaction, the oxidation number of Cr decreases from +6 to +3. Net decrease in the oxidation number of one Cr atom is 6−3=3. For 2 Cr atoms (in dichromate ion), the total decrease in the oxidation number is 2×3=6
The gram equivalent weight =
Total change in the oxidation number
gram molecular weight
=
6
294
=49
