Which of the following molecules exhibits ionic bonding?

The molecule that exhibits ionic bonding is sodium chloride (NaCl). Ionic bonding occurs when there is a transfer of electrons from one atom to another, typically between a metal and a non-metal. In NaCl, sodium (Na) is a metal that has one electron in its outer shell, while chlorine (Cl) is a non-metal that requires one additional electron to achieve a stable electron configuration.

When sodium transfers its electron to chlorine, it becomes a positively charged ion (Na⁺), and chlorine becomes a negatively charged ion (Cl⁻). The electrostatic attraction between these oppositely charged ions forms a strong ionic bond, resulting in the formation of NaCl, which has a crystalline structure and high melting and boiling points.

In contrast, the other molecules mentioned do not exhibit ionic bonding. For example, CCl₄ (carbon tetrachloride) has covalent bonds between carbon and chlorine atoms; H₂O (water) consists of polar covalent bonds between hydrogen and oxygen; and CH₄ (methane) involves covalent bonds between carbon and hydrogen. These types of bonding involve the sharing of electrons rather than the transfer of electrons seen in ionic bonding.