- Acids are compounds that contain hydrogen and non metals
- Acids can be classified as follows:
- Consist of two elements – A non-metal and Hydrogen
- Consist of 3 elements, a non-metal, Oxygen and Hydrogen.
(only Hydrogen and a non metal form the compound)
Naming Binary Acids
Hydrogen Chloride, (HCl) Hydrogen Sulphide (H2S), and other compounds formed by a NONMETAL and Hydrogen have acidic properties. These gases dissolve in water to form solutions which we call BINARY ACIDS.
When we say Hydrogen Chloride, we refer to the gas, when we say Chlorhydric acid we refer to the aqueous solution of the gas (liquid)
The name of the binary acid consists of two words. The first word has three parts. Do not forget to include the word ACID at the end of the name.:
root of non metal
Hydrosulphuric Acid or
HBr = hydro brom ic acid = hydrobromic acid OR Bromhydric acid
HF = hydro fluoric acid = hydrofluoric acid OR Fluorhydric acid
These are more difficult to name because these acids have hydrogen, a nonmetal, and may have varying numbers of oxygen atoms.
For example: H2SO4 and H2SO3 are acids. How do we name them?
To begin, we need a point of reference. Our reference point is this: The “ate” ions (sulfate, nitrate, etc) make the “ic” acids (sulfuric acid, nitric acid)
SO42-= sulfate ion è H2SO4 = sulfuric acid
NO3–= nitrate ion è HNO3 = nitric acid
Before naming Oxoacids, we need to setup some rules to name the POLYATOMIC IONS. (ZONE IN GREY INDICATE THAT THESE ELEMENTS DO NOT FORM OXOACIDS
All ATE ions will have three oxygen atoms in their formula with the exceptions of the ones highlighted in the table above with the number 4 in pink, which will have four. Hence, Carbonate ion, Nitrate ion, Chlorate ion, Bromate ion, etc will have 3 oxygen atoms, but Phosphate, Sulphate, etc, will have 4 oxygen atoms in their molecule.
The number of negative charges will be 2 for the EVEN groups (Silicate, Sulphate, Carbonate, -belong to an even number-) the rest will have one, with the exceptions of B, P and As, that will have 3 negative charges.