Question

which of the following is both an anion and a compound?
nacl
hco₃⁻
k⁺
na⁺
cl⁻

Explanation:

Step1: Define anion and compound

An anion is a negatively - charged ion. A compound is a substance made up of two or more different elements chemically combined.

Step2: Analyze each option

• $\text{NaCl}$: It is a compound but not an anion. It is a neutral ionic compound.
• $\text{HCO}_3^-$: It is a negatively - charged polyatomic ion (anion) and also a compound as it is made of hydrogen ($\text{H}$), carbon ($\text{C}$) and oxygen ($\text{O}$) atoms.
• $\text{K}^+$: It is a positively - charged ion (cation), not an anion.
• $\text{Na}^+$: It is a positively - charged ion (cation), not an anion.
• $\text{Cl}^-$: It is an anion but a single - element ion, not a compound in the sense of being made of multiple different elements.

Answer:

B. $\text{HCO}_3^-$