Which of the following is the correct formula for the sulfate ion?

• A. S_2O_3^{2-}
• B. SO_2^{2-}
• C. SO_4^{2-}
• D. SO_3^{2-}

Answer: (C)

Verified step by step guidance

1. Understand that the sulfate ion is a polyatomic ion composed of sulfur and oxygen atoms with a specific charge.
2. Recall the general formula for the sulfate ion, which consists of one sulfur atom bonded to four oxygen atoms, carrying a 2- charge.
3. Compare the given options to the known formula for sulfate: \(SO_4^{2-}\).
4. Identify that \(S_2O_3^{2-}\) is the formula for thiosulfate, \(SO_2^{2-}\) is the sulfite ion, and \(SO_3^{2-}\) is the sulfite ion as well, not sulfate.
5. Conclude that the correct formula for the sulfate ion is \(SO_4^{2-}\).