Final answer:
NaCl exhibits the most ionic character among the given compounds because it is formed by the transfer of electrons from the metal sodium to the non-metal chlorine, creating ions.
Step-by-step explanation:
The question asks which of the given compounds exhibits the most ionic character. Ionic character is most prevalent in compounds formed between metals and non-metals. An ionic compound involves the transfer of electrons, leading to the formation of cations and anions.
Among the compounds H₂O, CO₂, NaCl, and CH₄, NaCl shows the most ionic character. H₂O and CH₄ are both covalent compounds, where electrons are shared rather than transferred. CO₂, while also a covalent compound, has polar covalent bonds due to differences in electronegativity between carbon and oxygen. NaCl is composed of sodium (Na), a metal, and chlorine (Cl), a non-metal, which form ionic bonds by transferring electrons from Na to Cl, creating Na⁺ and Cl⁻- ions.