Final answer:
Hydrogen ions cannot exist by themselves in water as they quickly bond with other atoms or molecules.
Step-by-step explanation:
Hydrogen ions, also known as protons (H+), cannot exist by themselves in water due to their high charge density. When a hydrogen atom loses its electron, it becomes a hydrogen ion with a single positive charge. The positive charge of the hydrogen ion makes it highly attracted to any part of a nearby atom or molecule with an excess of negative charge.
In water, hydrogen ions immediately bond with un-ionized water molecules, forming hydronium ions (H3O+). This process is known as hydration. Hydronium ions completely suspend in water, but by convention, scientists refer to them as free hydrogen ions.
Therefore, option c) They quickly bond with other atoms or molecules is the correct answer to why hydrogen ions cannot exist by themselves.
The hydrogen ion (H+) cannot exist by itself because it quickly bonds with other atoms or molecules, due to its high charge density. When a hydrogen ion is generated in water, it does not remain free; it is immediately attracted to nearby un-ionized water molecules forming a hydronium ion (H3O+). This attraction is a consequence of the proton's very small size and high charge density, which creates an intense electric field that pulls it towards the negative charge found on other atoms or molecules. In water, this is typically the lone pair of oxygen atoms, resulting in the formation of the hydronium ion, which is much more stable than a free hydrogen ion.