Which one of the following is most likely to be an ionic compound?

• A. NaCl
• B. CO2
• C. H2O
• D. CH4

Answer: (A)

Verified step by step guidance

1. Step 1: Understand the difference between ionic and covalent compounds. Ionic compounds form when atoms transfer electrons, typically between metals and nonmetals, resulting in positive and negative ions held together by electrostatic forces.
2. Step 2: Identify the elements in each compound and their typical bonding behavior. For example, NaCl consists of sodium (a metal) and chlorine (a nonmetal), which commonly form ionic bonds.
3. Step 3: Analyze the other compounds: CO2, H2O, and CH4. These are composed of nonmetals only, which usually share electrons to form covalent bonds rather than transferring electrons.
4. Step 4: Recognize that NaCl is formed from a metal and a nonmetal, making it the most likely to be ionic, while the others are molecular covalent compounds.
5. Step 5: Conclude that among the given options, NaCl is the compound most likely to be ionic due to the nature of its constituent elements and bonding type.