If the below equation is balanced, then the values of x and y are
Cr2O72− + x H+ + 6 Fe2+ → 2 Cr3+ + 6 Fe3+ + y H2O
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → x = 14; y = 7
A redox equation in acidic medium is balanced so that atoms and charges are equal on both sides. Oxygen is balanced with \( \ce{H2O} \) and hydrogen with \( \ce{H^{+}} \).
The electron transfer is already balanced by the given coefficients: each Cr goes from +6 to +3 (2 × 3 = 6 electrons gained), and 6 \( \ce{Fe^{2+}} \) each lose one electron.
Oxygen: 7 O atoms on the left (in \( \ce{Cr2O7^{2-}} \)) must appear as water on the right, so y = 7.
Hydrogen: 7 \( \ce{H2O} \) contain 14 H atoms, which come from \( \ce{H^{+}} \), so x = 14.
\( \displaystyle \ce{Cr2O7^2- + 14H^+ + 6Fe^2+ -> 2Cr^3+ + 6Fe^3+ + 7H2O} \)
Charge check: left = −2 + 14 + 12 = +24; right = 6 + 18 = +24. Balanced.
Shortcut: x must be twice y (every \( \ce{H2O} \) takes two \( \ce{H^{+}} \)). Only Option (1) has x = 2y.
NCERT (2026-27 edition):
Oxides and Oxoanions of Metals – …
