What is the chemical formula for ferric chloride?

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Multiple Choice

What is the chemical formula for ferric chloride?

Ferric chloride contains iron in the +3 oxidation state. Chloride ions carry a -1 charge, so to balance the +3 charge of iron you need three chloride ions. Putting them together gives FeCl3, a neutral compound. The other options don’t balance to neutrality or reflect the correct oxidation state: FeCl2 would have iron in the +2 state (ferrous), FeCl would imply an improbable +1 state for iron, and Fe2Cl3 would not form a neutral, stable formula for ferric chloride. So the correct formula is FeCl3.

Ferric chloride contains iron in the +3 oxidation state. Chloride ions carry a -1 charge, so to balance the +3 charge of iron you need three chloride ions. Putting them together gives FeCl3, a neutral compound. The other options don’t balance to neutrality or reflect the correct oxidation state: FeCl2 would have iron in the +2 state (ferrous), FeCl would imply an improbable +1 state for iron, and Fe2Cl3 would not form a neutral, stable formula for ferric chloride. So the correct formula is FeCl3.

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