Termination “—OUS” is applied to the first of two elements when it exists in a greater proportion than in another combination with the same element, e.g., one atom of phosphorus and three atoms of chlorine form Phosphorous Chloride.
Termination “—IC,” when the first exists in a lesser proportion, e.g., one atom of phosphorus with five atoms of chlorine form Phosphoric Chloride.
Prefixes “MONO—,” “BI—,” “TRI—,” etc., indicate the proportion of the latter of two elements, and are sometimes used instead of the above termination. Thus phosphorous chloride may also be called Phosphorous Tri-Chloride; so one atom of carbon with one atom of oxygen is Carbon Monoxide.
Prefix “HYPO—” (under) and “PER—” (over), specify compounds formed by the same two elements containing less (or more) of an element than is in the usual compound.
Nomenclature of Salts.—From the common acids we get the following salts:—
| HCl | forms chlorides. |
| HNO3 | forms nitrates. |
| H2SO4 | forms sulphates. |
| H2S | forms sulphides. |
| H2CO3 | forms carbonates. |
| H2O | forms no salts. |
| H2SiO4 | forms silicates. |
| H3PO4 | forms phosphates. |
A rough rule for the nomenclature of acids may be made from the above. Acids with the prefix hydro and the suffix ic form salts in ide; with suffix ate, salts in ate; with suffix ous, salts in ite.
(16) Basicity.—The basicity of a substance is measured by the amount of hydrogen which it contains that can be replaced by a basic radical, e.g., H2SO4 is di-basic, i.e., the two atoms of hydrogen can be replaced by a basic radical. H2SO4 + CaCl2 = CaSO4 + 2HCl.
(17) Quantivalence.—The quantivalence of an element is measured by the number of atoms of hydrogen it combines with or replaces. E.g., Na is univalent, for when added to HCl it replaces one atom of hydrogen; Ca is bivalent, for, as seen in the above reaction, it replaces two atoms of hydrogen.
(18) Test for a Chloride.—To test for HCl or any chloride, add to the solution to be tested a little AgNO3, and if a chloride is present, a milky-white precipitate will be formed. The reaction is as follows: HCl + AgNO3 = AgCl (white precipitate) + HNO3. A metal almost invariably changes places with hydrogen.