Question 9 • Chemistry
Each Fe³⁺ ion has a charge of +3, and each O²⁻ ion has a charge of −2. Two Fe³⁺ ions give a total charge of +6, which balances the −6 charge from three O²⁻ ions. So the ratio of Fe³⁺ ions to O²⁻ ions is 2 to 3, choice C.
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