Final answer:
The oxygen atom in the hydronium ion (H3O+) shares one pair of its electrons with a hydrogen ion to form a coordinate covalent bond, thus correct answer is (B) shares with one of its electrons.
Step-by-step explanation:
When the coordinate covalent bond of the hydronium ion (H₃O⁺) is formed, the oxygen atom shares one of its electrons with a hydrogen ion (H+). To be more specific, the oxygen atom in H₂O has two lone pairs of electrons. When an additional hydrogen ion approaches, one of the lone pairs on the oxygen is used to form a coordinate bond with the hydrogen ion, resulting in the formation of H₃O⁺. This is because a coordinate bond involves one atom providing both electrons for the bond. In the case of hydronium ion formation, oxygen donates both electrons for the bond with the incoming hydrogen ion, meaning the correct answer is (B) shares with one of its electrons, where 'one of' refers to one of the lone pairs, or a single pair of electrons.