Acids, Bases, and Salts
In chemistry we differentiate between three electrolytes: acids, bases and salts.
Acids are chemical compounds which, when dissolved in water, produce a concentration of hydrogen ions, H+ (protons), greater than that of pure water. An acid is therefore a proton donor (proton = positively charged hydrogen ion H+).
Acids taste sour and turn litmus paper red. Litmus is the oldest and most often used indicator of whether a solution is an acid or a base. It is most often associated with pH measurement. Litmus is a pink dye derived from licheus, a plant organism composed of a fungus and an algae in symbiotic association.
The most common acids are:
Hydrochloric Acid |
HCI |
Component of Gastric Juices |
Nitric Acid |
HNO3 |
Used to Manufacture Dyes and Explosives |
Acetic Acid |
CH3COOH |
Vinegar |
Formic Acid |
HCOOH |
Used for Dyeing and Tanning |
Sulfuric Acid |
H2SO4 |
Batteries |
Phosphoric Acid |
H3PO4 |
Dental Cement, Fertilizer |
Bases are chemical compounds which, when dissolved in water, produce an excess of hydroxyl ions, OH- or accept protons – a base accepts protons. Bases taste bitter and turn litmus blue. A base feels slimy. The most common bases are:
Sodium Hydroxide (Caustic Soda) |
NaOH |
Drain and Oven Cleaner |
Calcium Hydroxide |
Ca(OH)2 |
Slated Lime (used in mortar for construction) |
Aluminium Hydroxide |
Al(OH)3 |
Raw Material for Aluminium Compounds |
Potassium Hydroxide (potash lye) |
KOH |
Soft Soap |
Magnesium Hydroxide |
Mg(OH)2 |
Milk of Magnesia |
Ammonia |
NH3 |
Household Cleaners |
Salts: When aqueous solutions of an acid and a base are combined, a neutralisation reaction occurs. This reaction takes place very rapidly and generally produces water and a salt. For example, sulfuric acid (H2SO4) and sodium hydroxide (NaOH), yield water and sodium sulfate (Na2SO4).
Salts are produced by substituting the H+ ion with a base part or by substituting the OH- ion with an acid part. Cations and anions combine to form an electrically neutral compound.
Examples:
Prior Article - The Ion and Dissociation
Download Our pH Measurement Guide
Get a better understanding of pH measurement in Hamilton’s comprehensive pH Measurement Guide.