Question

Why do HCl, HNO₃, etc., show acidic characters in aqueous solutions while solutions of compounds like alcohol and glucose do not show acidic character?

Answer 1

1. When HCl or HNO₃ are mixed with water then they dissolve in water to form H⁺ or H₃O⁺ ions which shows their acidic character.
2. For example just see the following reactions:
   1. $$\mathrm{HCl}(\mathrm{aq})⟶\mathrm{H}{\phantom{A}}^{+}+\mathrm{Cl}{\phantom{A}}^{-}$$
   2. $$\mathrm{H}{\phantom{A}}^{+}+\mathrm{H}{\phantom{A}}_2\mathrm{O}⟶\mathrm{H}{\phantom{A}}_3\mathrm{O}{\phantom{A}}^{+}$$
3. When alcohols and glucose are mixed with water then they do not dissolve to form ions. Hence they do not show acidic character.

Answer 2

1. Acids are substances that can dissociate on the dissolving of water, which results in production of hydrogen ions. Some acids show acidic character as they dissociate in the aqueous solution which results in the production of hydrogen ions (acids like HCl, HNO₃).
2. Compounds similar to glucose or alcohol also do contain hydrogen element but they do not show signs of acidic nature. This is due to the fact that the hydrogen in them will not separate as like the hydrogen in the acids. They will not separate to become hydrogen ions, on dissolving in the water.