Chemical Equilibrium: Overview, Questions, Preparation

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Salt Hydrolysis Lewis Acids and Bases Precipitation Titration Arrhenius Acid Hydrocyanic Acid

Updated on Jun 4, 2024 15:54 IST

In salt hydrolysis, an ion of a salt reacts with water. Although it may seem that salt solutions are always neutral, they can often be either basic or acidic. Salt hydrolysis is a reaction in which either an acidic or basic solution forms by one of the ions from a salt reacting with water.

Consider the salt formed when the strong base sodium hydroxide neutralises the weak acid, hydrofluoric acid. Below are the molecular and net ionic equations shown.

Hf(aq) + NaOH(aq) = NaF(aq) + H20(aq)

Hf(aq) +OH- (aq) = F- + H20(aq)

As sodium fluoride is soluble in the neutralisation reaction, the sodium ion is a spectator ion. To a certain amount, the fluoride ion can react with water, accepting a proton.

F-(aq) + H2O(aq) = HF(aq) + OH-(aq)

Based on hydrolysis, salts can be segregated into three categories:

Acidic salts
Neutral salts
Basic salts

Salt	Hydrolysis
Strong acid and base	Salts formed by the neutralisation of strong acid and strong base are neutral in nature since the bonds in the salt solution do not break apart. Typically, they get hydrated but do not hydrolyse. These salts are, thus, commonly known as neutral salts.
Weak acid and strong base	Salts formed by the neutralisation of weak acid and strong base are of basic nature.
Strong acid and weak base	Salts of strong acid and weak base formed by neutralisation are acidic in nature.
Weak acid and base salts	Weak acid and weak base neutralisation salts are acidic, basic or neutral, based on the existence of the acids and bases concerned.

Table of Contents

Salt Hydrolysis in Class 10:
Salt Hydrolysis in Class 11:
NCERT Illustrated Examples
FAQs on Salt Hydrolysis

Salt Hydrolysis in Class 10:

In the Class 10th textbook, in chapter Acids, Bases and Salts, there is well explained about the hydrolysis and different forms of salts.

Salt Hydrolysis in Class 11:

In Equilibrium Chapter, under the section ionic equilibrium, there is a lot about the Salts. Ionic equilibrium is one of the most important chapters in the 12th board as well as in the competitive exams.

NCERT Illustrated Examples

1. Which salts will undergo hydrolysis?

Answer - There is no hydrolysis of the salt from a heavy acid and a strong base. Therefore, only CH3COOK (strong base+weak acid) undergoes hydrolysis in water and provides the fundamental solution.

2. What is the degree of hydrolysis?

Answer - The proportion of cleaved peptide bonds in a protein hydrolysate is known as the degree of hydrolysis (DH). The pH-stat approach is based on the number of photons emitted during hydrolysis; the titration methods of TNBS, OPA, and formol are based on the calculation of hydrolysis-generated amino groups.

3. What is an example of a hydrolysis reaction?

Answer - An example of hydrolysis is the digestion of food when water tends to break down the compounds one has consumed. One substance formed by hydrolysis is soap. When a triglyceride or fat is hydrolysed, glycerin and fatty acids are formed.

FAQs on Salt Hydrolysis

Q: What happens when a salt undergoes hydrolysis?

A: Reverse neutralisation is hydrolysis. When salt is added in water, then the salt ions react with water, cation, anion, or both; the solution becomes either acidic or basic. This process is called hydrolysis. As a salt cation responds to water, a weak base and acid solution are formed.

Q: Does salt neutralise the acid?

A: Hydrolysis is a neutralisation reversal. As salt is put in water, the salt ions react with water, cation, anion, or both, and whether the solution becomes either acidic or basic, it is a hydrolysis process. As a salt cation reacts with water, it produces a weak base and acid solution.

Q: Which salt is maximum hydrolysed?

A: Maximum hydrolysis takes place in the salt of a weak acid and a weak base.

Q: What's the significance of hydrolysis?

A: A significant part of how the body splits food into its nutritional components is hydrolysis. In the shape of polymers that are much too heavy for your cells to use, the food you ingest reaches the body, so they have to be broken down into smaller monomers.

Q: How is the hydrolysis rate determined?

A: Through Nucleophilic Substitution or Elimination Mechanism.