Question

Which of the following ions are furnished by acids in aqueous solutions?
A. \[O{H^ - }\] ions
B. \[{H^ + }\] ions
C. \[{H_3}{O^ + }\] ions
D. None of These

Answer 1

Hint: To solve this question, it is required to have knowledge about the different acid-base concepts. According to the definition of acid by Lowry and Bronsted, and acid is a substance that furnishes \[{H^ + }\] ions in solution.

Complete answer:
> When in an aqueous solution, the acid molecules dissociate to liberate the hydrogen ions as the \[{H^ + }\] ions. These hydrogen ions are also called protons because hydrogen has only one electron in its valence shell and after losing it only a proton remains in the nucleus. But these protons are not at all stable because a lone proton has a strong affinity for electrons.
> So, these protons search for a pair of electrons to get stability which is provided by the lone pair of electrons present in the water molecules surrounding the protons. Hence the protons accept the lone pair of electrons on the oxygen atom to form the hydronium ions through coordinate covalent bonding, leaving a positive charge on the oxygen atom of the water molecules. 

> The reaction can be presented as follows:
\[{H^ + }\]+ ${H_2}O$$ \rightleftarrows $\[{H_3}{O^ + }\]

So, the correct answer is option C.

Note: Any compound that dissolves in water to release hydronium ion as the only positive ion is called an acid. An acid can be represented by the general formula $HX$, where $H$ is hydrogen and $X$ is generally a more electronegative atom or (a group of atoms, that has more negative formal charge) than hydrogen. The Lewis acids on the other hand are electron pair acceptors.