Salts

1. A salt is formed by the replacement of hydrogen ions in an acid by metallic ions or ammonium ion
2. Soluble salts are prepared from their reaction with acids

a)     Reaction of acids with alkalis

b)     Reaction of acid with insoluble metallic oxides or hydroxides

c)     Reaction of acids with more electropositive metal such as zinc and magnesium (excepts potassium, sodium and calcium)

d)     Reaction of acids with metallic carbonates.

3. Insoluble salts are prepared by the precipitation method through double decomposition reaction
4. When a hot saturated aqueous solution is allowed to cool, the bits of solid that precipitate are called crystals. All crystals share the following common characteristic:

a)     They have flat face, straight edges and sharp corners

b)     They have two adjacent faces that meet at a fixed angle.

c)     Crystals of the same substance have fixed geometric shapes

d)     Crystals of the same substance have the same shape although the size may differ

5. The molar ration of the cations and the anions which combines to form the salt can be determining experimentally through the continuous variation method. Hence, the chemical formula and the ionic equation of the salts can be constructed.
6. In the continuous variation method, a fixed volume of a solution is mixed with various volume of another solution to determine the molar ratio of the ions of the both solution.

Qualitative Analysis of Salts

1. Certain cations can be identified by the colour of their precipitates formed when the aqueous solution of its salt react with aqueous sodium hydroxide or aqueous ammonia solution
2. Certain anions can be identified by heating the solid and test the gases given off as well as identifying the colour of the residues.
3. Some cations confirmation test through reaction with specific reagents

EXERCISE

1. You are given two colourless solution, namely water and a dilute acid solution

Describe three chemical test to detect which of the solution is an acid.

2. Beginning with copper (II) oxide, describe how you can prepare a sample pf copper sulphates salt
3.  
1. You are given four solution containing sulphate, nitrate, chloride and carbonate ions. Describe a series of test to identify each of the ions
2. You are given four solution containing Mg²⁺ , Al³⁺ , Zn²⁺ and Pb^2+. Describe a series of test to identify each of the ions.