Which of the following compounds is an example of an ionic compound?

Ionic compounds are formed when atoms transfer electrons, resulting in the formation of charged ions that attract each other due to their opposite charges. Sodium chloride (NaCl) is a classic example of this type of bond. In NaCl, sodium (Na) donates an electron to chlorine (Cl), creating a positively charged sodium ion (Na⁺) and a negatively charged chloride ion (Cl⁻). The resulting attraction between these ions leads to the formation of a strong ionic bond, characteristic of ionic compounds.

In contrast, the other compounds listed do not exhibit this type of bonding. Water (H2O) is a polar covalent compound where electrons are shared between hydrogen and oxygen atoms, but not transferred. Carbon dioxide (CO2) consists of covalent bonds formed by sharing electrons between carbon and oxygen. Glucose (C6H12O6) is a complex organic molecule with many covalent bonds, where carbon and hydrogen share electrons without forming ions. Therefore, NaCl stands out as the only compound in the list that is classified as an ionic compound due to its electron transfer and the resultant ionic bonding.