alleryThe oxidation state of chromium in both CrO₄²⁻ and Cr₂O₇²⁻ is:
A+6 (same in both species)
B+5
C+3
D+7
Answer & Solution
Correct answer: A. +6 (same in both species)
Chromate (CrO₄²⁻): x + 4(−2) = −2 → x = **+6**.
Dichromate (Cr₂O₇²⁻): 2x + 7(−2) = −2 → 2x = 12 → x = **+6**.
Inter-conversion is just by pH (alkaline ↔ acidic), no change in Cr oxidation state.
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