```Hydrolysis of Amphiprotic Anion:
Let us consider hydrolysis of amphiprotic anion only, i.e., when counter cation is not hydrolysed, example of some salts of this category are NaHCO3, NaHS, Na2HPO4, NaH2PO4.

Here, H2PO-4 and HPO2-4  are amphiprotic anions. pH after their hydrolysis can be calculated as,
pH of  H2PO-4  in aqueous medium = (pka1 + pka2)/2
pH of H2PO2-4  in aqueous medium = (pka2 + pka3)/2

Here, H2PO2-4  is conjugate base of H2PO-4 and H3PO4 is conjugate acid of H2PO-4.
Similarly, PO3-4 is conjugate base of HPO-24  and HPO-4  is conjugate acid of PO3-4 .

(iv)  Let us consider amphiprotic bicarbonate anion.

pH HCO-3of  ion after hydrolysis in aqueous medium

= (pka1 + pka2)/2

(v)  Let us consider the hydrolysis of amphiprotic anion along with cation, e.g., NH4HCO3, NH4HS.
In above examples both cations and anions are derived from weak base and weak acids respectively hence, both will undergo hydrolysis in aqueous medium.
When these salts are dissolved in water, [H3O+] concentra­tion can be determined as,
[H3O+] = √ka1[kw/kb + ka2]
pH = -log = √ka1[kw/kb + ka2]
Hydrolysis at a Glance

Salt

Nature

Degree

Hydrolysis Constant

pH

1.   NaCl
(Strong acid + Strong Base)

2. Ch3COONa (Weak acid + Strong base)

3. NH4Cl
(Strong acid + Weak base)

4. CH3COONH4   (Weak     acid + Weak base)

Neutral

Base

Acidic

*

No Hydrolysis

h = √kw/Cka

h = √kw/Ckb

h = √kw/(ka + kb)

-

Kh = kw/ka

Kh = kw/Ckb

Kh = kw/(ka + kb)

-

pH=1/2[pkw + pka + logC]

pH=1/2[pkw- pkb - logC]

pH=1/2[pkw + pka - pkb]

In the case of salt of weak acid and weak base, nature of medium after hydrolysisis decided in the following manner:
(i)    If Ka = Kb, the medium will be neutral.
(ii)  If Ka > Kb, the medium will be acidic.
(iii)  If Ka < Kb, the medium will be basic.
The degree of hydrolysis of salts of weak acids and  weak bases is unaffected by dilution because there is no concentration  term in the expression of degree ofhydrolysis.

Note : Degree of hydrolysis always increases with increase in temperature because at elevated temperature increase in Kw is greater as compared to Ka and Kb.```
Related Resources
Relative Strength of Acids and Bases

Relative Strength of Acids and Bases: According to...

Salt of Strong Acid and Weak Base

Salt of a strong acid and a weak base: The...

Solubility Product

SOLUBILITY PRODUCT: If to a given amount of...

Salt of Weak Acid and Weak Base

Salt of a weak acid and a weak base: Maximum...

Salt of Weak acid and Strong Base

Salt of a Weak Acid and a Strong Base: The...

Common ION Effect

COMMON ION EFFECT: Let AB to the weak electrolyte....

Acids and Bases

Acids and Bases: The earliest criteria for the...

Periodic Variations of Acidic and Basic Properties

Periodic variations of acidic and basic...

Salt Hydrolysis

Salt Hydrolysis: Pure water is a weak electrolyte...

Buffer Capacity

Buffer capacity: The property of buffer solution...

pH OF Weak Acids and Bases

pH OF Weak Acids and Bases: Weak acids and bases...

Buffer Solutions

BUFFER SOLUTIONS: For several purposes, we need...

Relationship-Solubility and Solubility Product

Relationship between solubility and solubility...

Types of Electrolytes

Types of Electrolytes: The compounds which give...

Ostwald s Dilution Law

Ostwald’s Dilution Law: According to...

Lewis Concept of Acids and Bases

Lewis Concept of Acids and Bases: This concept was...

Hendersons Equation

Henderson's Equation (pH of a buffer): (i) Acidic...

Acid-Base Neutralization

ACID-BASE NEUTRALISATION-SALTS When aqueous...

Hydrogen Ion Concentration pH Scale

HYDROGEN ION CONCENTRATION-pH SCALE: It is clear...

Applications of Solubility Product

Applications of Solubility Product (i)...

Ionic Product of Water

Ionic Product of Water: Pure water is a very weak...

Theory of Indicators

Ionic Equilibrium THEORY OF INDICATORS: An...