Which of the Following is Both an Anion and a Compound

Question

Which of the following is both an anion and a compound?
A) Na+
B) Cl-
C) K+
D) HCO3-
E) NaCl

Accepted Answer

An anion is an ion with a negative charge. The only option that is a compound and an anion is HCO3-, which is the bicarbonate ion. Na+ and K+ are cations, Cl- is an anion but not a compound, and NaCl is a compound but not an anion.