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What is meant by Family of Salts?

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We have a good understanding of acids and bases in modern chemistry (also called alkalis). Acids and bases are utilised as laboratory reagents, industrial catalysts, culinary additives, and cleaning products, and they pervade our life from the laboratory to the kitchen. However, it took centuries for chemists to completely comprehend these chemicals over the course of history. 

What are Salts?

Salts are ionic substances that are formed when an acid and a base react to neutralise each other. Salts have no electrical charge. 

There are many other types of salts, but sodium chloride is the most prevalent. Table salt or common salt are both terms for sodium chloride. Sodium chloride is used to make meals taste better. 

Characteristics of Salts are:

  • The majority of the salts are crystalline in nature.
  • Transparent or opaque salts are available.
  • The majority of salts are water-soluble.
  • In their molten condition, salt solutions transmit electricity as well.
  • Salt can be salty, sour, sweet, bitter, or umami in flavour (savoury).
  • Neutral salts have no odour.
  • Colourless or coloured salts are available.

Properties of Salts are:

The sodium chloride in the molecule exhibits characteristics that are considerably different from those of the elements sodium and chlorine.

  1. Saltwater is a good conductor of electricity because it contains ions.
  2. The ions are held together by electrostatic attraction, and a chemical connection is formed between them.

Types of Salts

  • Acidic salt- An acidic salt is a salt generated by partial neutralisation of a diprotic or polyprotic acid. These salts contain an ion that can be ionised, as well as another cation. The anion is mostly made up of the ionizable H+. In baking, certain acid salts are utilised. e.g. NaHSO4­, KH2PO4 etc.
  • Basic or Alkali Salt- A basic salt is a salt that is generated when a strong base is partially neutralised by a weak acid. They break down into a basic solution when they are hydrolyzed. This is due to the fact that when a basic salt is hydrolyzed, the conjugate base of a weak acid is produced in the solution. e.g. White lead (2PbCO3·Pb(OH)2) etc.
  • Double salt- Double salts are those that have more than one cation or anion in them. They are made by combining two distinct salts that have crystallised in the same ionic lattice. e.g. Potassium sodium tartrate (KNaC4H4O6.4H2O) also known as Rochelle salt.
  • Mixed Salts- Mixed salt is a salt that is composed of a predetermined mixture of two salts that often share a common cation or anion. e..g. CaOCl2.

Hydrolysis of a Salt: The reaction of salt with water is known as salt hydrolysis. A neutralisation reaction is the inverse of this reaction. The component acid and base are generated as results when salt reacts with water in this process. The salt dissociates into ions during hydrolysis, either entirely or partially depending on the salt’s solubility product.

Family of Salt

Salts with similar acidic or basic radicals are classified as belonging to the same family.

For example:

  • The chloride family includes sodium chloride (NaCl) and calcium chloride (CaCl2).
  • The calcium family includes calcium chloride (CaCl2) and calcium sulphate (CaSO4).
  • The zinc family includes zinc chloride (ZnCl2) and zinc sulphate (ZnSO4).

Neutral, Acidic and Basic Salts

1. Neutral Salts

In nature, salts formed by the interaction of a strong acid and a strong base are neutral. Such salts have a pH of 7, which is considered neutral. Sodium chloride, sodium sulphate and potassium chloride.

For example:

  • Sodium chloride (NaCl):  It is created when hydrochloric acid (a powerful acid) reacts with sodium hydroxide (a strong base).

NaOH + HCl → NaCl + H2O

  • Sodium Sulphate (Na2SO4): It is created when sodium hydroxide (a strong basic) reacts with sulphuric acid ( a strong acid). 

2NaOH + H2SO4 → Na2SO4 + 2H2O

  • Potassium Chloride (KCl): It is created when potassium hydroxide (a strong base) reacts with hydrochloric acid (a strong acid). 

KOH + HCl → KCl + H2

2. Acidic Salts

Acidic salts are the salts that result from the reaction of a strong acid and a weak base. Acidic salt has a pH value of less than 7. Ammonium sulphate, ammonium chloride, and other ammonium compounds are examples.

For example:

  • Ammonium chloride: Hydrochloric acid (a powerful acid) reacts with ammonium hydroxide to produce ammonium chloride (a weak base). 

NH4OH + HCl → NH4Cl + H2O

  • Ammonium sulphate: After a reaction between ammonium hydroxide (a weak base) and sulphuric acid, ammonium sulphate is produced (a strong acid).

2NH4OH + H2SO4 → (NH4)2SO4 + 2H2O

3. Basic Salts

Basic salts are the salts that result from the reaction of a weak acid and a strong base. Sodium carbonate, sodium acetate, and other salts are examples.

For example:

  • Sodium carbonate: The interaction between sodium hydroxide (a strong base) and carbonic acid produces sodium carbonate (a weak acid)

H2CO3 + 2NaOH → Na2CO3 + H2O

  • Sodium acetate: After a reaction between a strong base, sodium hydroxide (a strong base), and acetic acid, sodium acetate is produced (a weak acid)

CH3COOH + NaOH → CH3COONa + H2O

Cause of formation of acidic, basic and neutral salts: 

  • When a strong acid combines with a weak base, the base cannot neutralise the acid completely. As a result, an acidic salt forms.
  • The acid is unable to fully neutralise a strong base when it combines with a weak acid. As a result, a basic salt is generated.
  • When an acid and a base of equal strength react, they completely neutralise each other. This results in the formation of a neutral salt.

pH value of salts

  • A neutral salt has a pH value that is nearly equal to 7.
  • A salt that is acidic has a pH value of less than 7.
  • A basic salt is one that has a pH value greater than 7.

Sample Problems

Problem 1: When the pH of the mouth falls below 5.5, why does tooth decay begin?

Solution:

When the pH of our mouth falls below 5.5, tooth decay begins. This is because below this pH value, the mouth’s medium becomes more acidic, causing tooth enamel to deteriorate more quickly.

Problem 2: The pH of fresh milk is 6. Will its pH value rise or fall when it transforms into curd (yoghurt)? Why?

Solution:

The pH of milk decreases as it turns into curd (yoghurt). This is because lactic acid is formed during the curd’s production, making it sour.

Problem 3: What is the definition of neutralisation? 

Solution:

Neutralisation is the reaction between an acid and a base. Salt and water are generated as a result of the growth of heat in this process. 

Acid + Base ➝ Salt + Water + (heat is evolved)

For example:

HCl + NaOH ➝  NaCl + H2O

Problem 4: What are the practical applications of the neutralisation reaction?

Solution:

Neutralization aids us in a variety of ways in our daily lives. The following are some of the applications:

  1. When we have acid reflux, we take an antacid to help us feel better. An antacid counteracts the effects of too much acid.
  2. When an ant bites, a moist baking soda or calamine solution is applied on the skin to neutralise the action of the acid injected into the skin.
  3. Plants do not grow well in soil that is either excessively acidic or too basic. When the soil is excessively acidic, it is treated with bases such as quick lime or slaked lime, and when it is too basic, it is amended with organic matter. Organic stuff produces acids, which balance out the soil’s basic nature.
  4. Factory wastes: Factory wastes contain acids, which are toxic to aquatic life. Basic compounds are added to these wastes to neutralise them.

Problem 5: Write properties of salts.

Solution:

Properties of salts are:

  1. Saltwater is a good conductor of electricity because it contains ions.
  2. The ions are held together by electrostatic attraction, and a chemical connection is formed between them.

Problem 6: Write the characteristics of salts.

Solution:

Following are the characteristics of salts:

  • The majority of the salts are crystalline in nature.
  • Transparent or opaque salts are available.
  • The majority of salts are water soluble.
  • In their molten condition, salt solutions transmit electricity as well.
  • Salt can be salty, sour, sweet, bitter, or umami in flavour (savoury).
  • Neutral salts have no odour.
  • Colorless or coloured salts are available.

Problem 7: What will happen when hydrochloric acid reacts with ammonium hydroxide?

Solution:

Hydrochloric acid (a powerful acid) reacts with ammonium hydroxide to produce ammonium chloride (a weak base).

The reaction is :

NH4OH + HCl → NH4Cl + H2O



Last Updated : 01 Sep, 2021
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