Acids

Acids

  1. Acids form a class of chemical substances which contain hydrogen ions in aqueous solution, H+ (aq), as the only positive ion.
  2. Acids are usually classified into mineral or organic acids.

Mineral Acids

  1. generally much stronger
  2. most do not occur naturally
  3. usually have simpler molecules

Example

  • Sulphuric Acid
  • Nitric Acid
  • Hydrochloric Acid
  • Phoshoric Acid
  • Carbonic Acid
Organic Acids
  1. naturally occurring
  2. found in vegetables, fruit and other foodstuffs
  3. usually weaker and less corrosive

Example

  • Ethanoic Acid
  • Citric Acid
  • Lactic Acid
  • Tartaric Acid
  • Acetic Acid
  1. Acids are substances that form hydrogen ions when dissolved in water.
  2. A hydrogen ion is actually a proton. Therefore, acids are called the proton donors.

Examples
\[HCl\xrightarrow{{{H_2}O}}{H^ + } + C{l^ – }\]
\[HN{O_3}\xrightarrow{{{H_2}O}}{H^ + } + N{O_3}^ – \]
\[{H_2}S{O_4}\xrightarrow{{{H_2}O}}2{H^ + } + S{O_4}^{2 – }\]

The hydrogen ions produced will combine with the water molecule to form hydroxonium ions (H3O+)
\[{H^ + } + {H_2}O \to {H_3}{O^ + }\]
Therefore the reaction can also be written as
\[HCl + {H_2}O \to {H_3}{O^ + } + C{l^ – }\]
\[HN{O_3} + {H_2}O \to {H_3}{O^ + } + N{O_3}^ – \]
\[{H_2}S{O_4} + 2{H_2}O \to 2{H_3}{O^ + } + S{O_4}^{2 – }\]