Salt hydrolysis of strong acid and weak base

When we prepare an aqueous solution of Ammonium Nitrate (NH₄AT THE₃) we can see that its pH is below 7.

The addition of NH₄NH₃ to water makes the solution acidic.
To obtain the equation of the salt hydrolysis process, we must follow the following rules:
• dissociate the salt (separate the cation from the anion)
• ionize strong acid (HA → H⁺ + A^-)
• dissociate the strong base (COH → C⁺ + OH^-)

• NH4NO3, as it is a soluble salt, it is dissociated:
NH4NO3 → NH+4 + NO-3

• HNO3, as it is strong acid, is ionized:
HNO3 → H+ + NO-3

Thus, the most correct way to represent the reaction is:

Note that the hydrolysis was of the cation, that is, the ion coming from the weak base.
Cation hydrolysis: NH⁴⁺ + HOH ↔ NH₄OH+H⁺
The saline hydrolysis of ammonium nitrate gave rise to the products:
NH₄OH (ammonium hydroxide): weak base
HNO₃ (nitric acid): strong acid
The presence of the H+ ion justifies the acidity of the solution (pH < 7).
Conclusion:
Strong acid salt and weak base give the solution an acidic character.

By Líria Alves
Graduated in Chemistry
Brazil School Team

See more! saline hydrolysis

Physicochemical - Chemistry - Brazil School

Source: Brazil School - https://brasilescola.uol.com.br/quimica/hidrolise-salina-acido-forte-base-fraca.htm