Which of the following is the correct chemical formula for the acetate polyatomic ion?

• A. C_2O_4^{2-}
• B. NO_3^-
• C. CH_3COO^-
• D. CO_3^{2-}

Answer: (C)

Verified step by step guidance

1. Step 1: Understand what a polyatomic ion is — it is a charged species composed of two or more atoms covalently bonded, that acts as a single ion in chemical reactions.
2. Step 2: Review the given options and identify their common names and formulas: \(\mathrm{C_2O_4^{2-}}\) is oxalate, \(\mathrm{NO_3^-}\) is nitrate, \(\mathrm{CH_3COO^-}\) is acetate, and \(\mathrm{CO_3^{2-}}\) is carbonate.
3. Step 3: Recall that the acetate ion specifically has the formula \(\mathrm{CH_3COO^-}\), which consists of two carbon atoms, three hydrogen atoms, and two oxygen atoms with a single negative charge.
4. Step 4: Compare the formulas to confirm that \(\mathrm{CH_3COO^-}\) matches the acetate ion, while the others correspond to different polyatomic ions.
5. Step 5: Conclude that the correct chemical formula for the acetate polyatomic ion is \(\mathrm{CH_3COO^-}\).