Acid is any substance that tastes sour in water solution, changes the colour of certain indicators (e.g., reddens blue litmus paper), reacts with metals (e.g., iron) to liberate hydrogen,
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reacts with bases to form salts, and promotes certain chemical reactions (acid catalysis).
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Arrhenius acid is any species that increases the concentration of H+ in aqueous solution. An Arrhenius acid is any species that increases the concentration of H+ ions—or protons—in aqueous solution.
HCl(aq)→H+(aq)+Cl− (aq)
** Types of Acids**
Binary hydrides: . Binary acids are all written in “H-A” form, which means hydrogen bond to a nonmetal atom.
NaH+H2O→Na++OH–+H2oxyacid: it has to have one or more O-H bonds, example are, Sulfuric Acid H2SO4, Nitric Acid HNO3
carboxylic acid: only the hydrogen atom in the carboxyl group can be ionized and contribute to acidity. example, Benzoic acid