Saltsandtheirpreparation Powerpoint 121116100612 Phpapp02
SALTS AND THEIR PREPARATION
SALTS
A salt is a compound formed when the hydrogen ions in an acid are replaced by metal ions or by ammonium ions.
Compounds in which the H+ ions in an acid have been replaced by ammonium ions (NH4+) are called ammonium salts.
NOTE:
•An anion is a negatively charged ion. Hence:•Hydrochloric acid gives chlorides. E.g. sodium chloride, ammonium chloride.
•Nitric acid gives nitrates. E.g. barium nitrate, copper nitrate.
•Sulphuric acid gives sulphates. E.g. silver sulphate, iron (ii) sulphate. •Phosphoric acid gives phosphates. E.g. sodium phosphate, ammonium phosphate.
•Each acid gives rise to a series of salts named by the ANION which they contain.
•Some acids can donate more than one replaceable hydrogen ion
(proton)
•E.g. sulphuric acid (H2SO4) and phosphoric acid (H3PO4).
•Sulphuric acid can give rise to two series of salts and phosphoric acid to three series of salts depending on how many protons are replaced.
•i.e. (a) H2SO4 → NaHSO4 → Na2SO4
(b) H3PO4 → NaH2PO4 → Na2HPO4 → Na3PO4
•NORMAL SALTS- These are salts which do not contain replaceable hydrogen. E.g. sodium chloride (NaCl).
•ACIDIC SALTS-These are salts which contain replaceable hydrogen. This is because when the hydrogen is replaced they are acting like an acid.
E.g. sodium hydrogen sulphate (NaHSO4).
•The method chosen to prepare a salt depends on its solubility.
•Solubility depends on the combination of positive and negative ions.
SOLUBILITY RULES
SOLUBLE
INSOLUBLE
1
All nitrates
All carbonates except for sodium, potassium and ammonium carbonates 2
All chlorides except for silver chloride and lead (ii) chloride
All sulphides except for sodium, potassium and ammonium sulphides 3
All sulphates except for calcium, barium and lead (ii) sulphates
All oxides except for sodium potassium and ammonium oxides 4 All sodium, potassium (even other group I elements), ammonium and nitrate compounds are soluble
All hydroxides except for sodium, potassium(group I),
SALTS
A salt is a compound formed when the hydrogen ions in an acid are replaced by metal ions or by ammonium ions.
Compounds in which the H+ ions in an acid have been replaced by ammonium ions (NH4+) are called ammonium salts.
NOTE:
•An anion is a negatively charged ion. Hence:•Hydrochloric acid gives chlorides. E.g. sodium chloride, ammonium chloride.
•Nitric acid gives nitrates. E.g. barium nitrate, copper nitrate.
•Sulphuric acid gives sulphates. E.g. silver sulphate, iron (ii) sulphate. •Phosphoric acid gives phosphates. E.g. sodium phosphate, ammonium phosphate.
•Each acid gives rise to a series of salts named by the ANION which they contain.
•Some acids can donate more than one replaceable hydrogen ion
(proton)
•E.g. sulphuric acid (H2SO4) and phosphoric acid (H3PO4).
•Sulphuric acid can give rise to two series of salts and phosphoric acid to three series of salts depending on how many protons are replaced.
•i.e. (a) H2SO4 → NaHSO4 → Na2SO4
(b) H3PO4 → NaH2PO4 → Na2HPO4 → Na3PO4
•NORMAL SALTS- These are salts which do not contain replaceable hydrogen. E.g. sodium chloride (NaCl).
•ACIDIC SALTS-These are salts which contain replaceable hydrogen. This is because when the hydrogen is replaced they are acting like an acid.
E.g. sodium hydrogen sulphate (NaHSO4).
•The method chosen to prepare a salt depends on its solubility.
•Solubility depends on the combination of positive and negative ions.
SOLUBILITY RULES
SOLUBLE
INSOLUBLE
1
All nitrates
All carbonates except for sodium, potassium and ammonium carbonates 2
All chlorides except for silver chloride and lead (ii) chloride
All sulphides except for sodium, potassium and ammonium sulphides 3
All sulphates except for calcium, barium and lead (ii) sulphates
All oxides except for sodium potassium and ammonium oxides 4 All sodium, potassium (even other group I elements), ammonium and nitrate compounds are soluble
All hydroxides except for sodium, potassium(group I),