ACID

• An ACID is a substance whose molecules yield hydrogen ions (H+) when dissolved in water. They are an important class of hydrogen containing compounds.
• Acid solutions are identified by the way they affect colors of some indicators. Litmus paper and phenolphthalein are two such indicators.
• blue to red = acidic
• red to blue = basic
• PROPERTIES OF ACIDS

  1.) They have sour taste.

  2.) They contain ionizable hydrogen which in water solution exist as positive ion (H+).

  3a.) They react with most metals releasing hydrogen gas and at the same time producing salts.

  3b.) They also react with oxides of metals producing salt and water.

  4.) Acids neutralize bases or vice-versa producing salt and water.
• Acetic acid is produced by the process called FERMENTATION
• With the subsequent action of oxygen in air, the alcohol is converted to acetic acid and water. Such a process is known as oxidation.
• The presence of positive and negative ions which are free to move around at random among water molecules in aqueous acids makes the solution a conductor of electricity.
• Sulfuric acidsolution isutilized as an electrolyte, a medium for electronsto travel between the lead and lead dioxideelectrodes of a storage battery.
• Scales and rust removal is accomplished by the above mentioned chemical reactions. Such a process is known as pickling.
• ”Leather Manufacture” In this industry, lactic acid, (CH3CH(OH))COOH is used in treating prepared animal skins (hide).
• Tanning is the process of treating skins and hides of animals to produce leather. A tannery is the place where the skins are processed. Tanning hide into leather involves a process which permanently alters the protein structure of skin, making it more durable and less susceptible to decomposition, and also possibly coloring it.
• Strong acids - give relatively high concentration of hydrogen ions because they ionize completely or nearly so in solution.
• Strong acids - give relatively high concentration of hydrogen ions because they ionize completely or nearly so in solution. Examples: Mineral Acids (acids prepared from minerals on earth): Nitric acid, Hydrochloric acid, sulfuric acid and other inorganic acids
• Weak acids - give low concentration of hydrogen ions in solution (ionize slightly when in solution) Examples: Organic acids : acetic acid (vinegar), citric acid (lemon, oranges) lactic acid (milk).
• Phenolphthalein becomes colorless in acidic solutions