A salt is an ionic compound that has a cation other than H+ and an anion other than OH– and is obtained along with water in the neutralization reaction between acids and bases. It is present in large quantities in seawater, where it is the main mineral constituent. Salt is essential for animal life and saltiness is one of the basic human tastes.
Eg:- NaCl, CuCl2 etc.
Acid + Base \(\rightarrow\) Salt + water
Types of Salt:
- Acidic Salt:- The salt formed by partial neutralization of a diprotic or a polyprotic acid is known as an acidic salt. These salts have ionisable H+ ion along with another cation. Mostly the ionisable H+ is a part of the anion. Some acid salts are used in baking.
For eg:- NaHSO4 , KH2PO4 etc.
H2SO4 + NaOH \(\rightarrow\) NaHSO4 + H2O
- Basic or Alkali Salt:- The salt formed by the partial neutralization of a strong base by a weak acid is known as a basic salt. They hydrolyze to form a basic solution. It is because when hydrolysis of basic salt takes place, the conjugate base of the weak acid is formed in the solution.
For eg:- White lead (2PbCO3·Pb(OH)2).
- Double salt:- The salts that contain more than one cation or anion are known as double salt. They are obtained by the combination of two different salts crystallized in the same ionic lattice.
For eg:- Potassium sodium tartrate (KNaC4H4O6.4H2O) also known as Rochelle salt.
- Mixed Salts:- The salt that consists of a fixed proportion of two salts, often sharing either a common cation or common anion is known as mixed salt.
For e.g. :- CaOCl2
Hydrolysis of a salt
Hydrolysis of salt refers to the reaction of salt with water. It is the reverse of a neutralization reaction. In this reaction, when salt undergoes reaction with water, the constituent acid and base are formed as products. In hydrolysis, salt dissociates to form ions, completely or partially depending upon the solubility product of that salt.
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