Which of the following is a correct formula and name for a common polyatomic ion?

• A. PO_4^- (phosphate)
• B. CO_3^2- (chlorate)
• C. SO_4^2- (sulfite)
• D. NO_3^- (nitrate)

Answer: (D)

Verified step by step guidance

1. Step 1: Understand that polyatomic ions are ions composed of two or more atoms covalently bonded, carrying an overall charge.
2. Step 2: Review the common polyatomic ions and their correct formulas and charges, such as phosphate (PO_4^{3-}), chlorate (ClO_3^-), sulfate (SO_4^{2-}), sulfite (SO_3^{2-}), and nitrate (NO_3^-).
3. Step 3: Compare each given formula and name pair to the known correct polyatomic ions: PO_4^- is incorrect because phosphate has a 3- charge, CO_3^{2-} is carbonate, not chlorate, and SO_4^{2-} is sulfate, not sulfite.
4. Step 4: Identify that NO_3^- corresponds correctly to nitrate, which is a common polyatomic ion with a single negative charge.
5. Step 5: Conclude that the correct formula and name pair among the options is NO_3^- (nitrate).