When Metal displaces Hydrogen atoms from the acids, it liberates Hydrogen gas with a formation of a compound called "Salt".

[Acid + Metal --> Salt + Hydrogen gas↑].

Example:-
* Acid - Sulphuric Acid (H2SO4).
* Metal - Zinc (Zn).

Reaction of Acid (H2SO4) with metal (Zn).

H2SO4 + Zn ==> ZnSO4 + H2↑.


[Here, Zinc Sulphate (ZnSO4) is a salt].

Salt is a substance that is formed by the reaction of an acid with a base or an alkali. It is an ionic compound that is made up of positively charged ions called cations and negatively charged ions called anions. Salt is an important chemical substance and is used in many industries, including food, medicine, and agriculture.

Formation of salt

Salt is formed by the reaction between an acid and a base or an alkali. The acid donates a hydrogen ion (H+) to the base, which accepts it to form water (H2O). The remaining ions from the acid and base combine to form a salt.

For example, when hydrochloric acid (HCl) reacts with sodium hydroxide (NaOH), it forms sodium chloride (NaCl) and water (H2O).

HCl + NaOH → NaCl + H2O

Properties of salt

- Salt is a crystalline solid that is usually white in color.
- It has a high melting and boiling point.
- Salt is soluble in water and forms an electrolyte solution.
- It is a good conductor of electricity in the molten state or in an aqueous solution.
- Salt is generally tasteless and odorless, but some salts may have a salty or bitter taste.

Types of salt

- Acidic salt: These salts are formed when only a part of the replaceable hydrogen atoms of the acid are replaced by a metal or a basic radical. For example, sodium hydrogen carbonate (NaHCO3) is an acidic salt that is formed by the partial replacement of hydrogen ions in carbonic acid (H2CO3) by sodium ions (Na+).
- Basic salt: These salts are formed when a metal ion combines with a basic radical to form a salt that has a basic character. For example, magnesium hydroxide (Mg(OH)2) is a basic salt that is formed by the combination of magnesium ions (Mg2+) and hydroxide ions (OH-).
- Double salt: These salts are formed when two different salts are combined to form a new compound. For example, potassium aluminum sulfate (KAl(SO4)2) is a double salt that is formed by the combination of potassium sulfate (K2SO4) and aluminum sulfate (Al2(SO4)3).

Uses of salt

- Salt is used as a food preservative and seasoning.
- It is used in the production of chemicals such as sodium hydroxide, chlorine, and hydrogen.
- Salt is used in the production of glass and ceramics.
- It is used in water treatment to remove impurities.
- Salt is used in agriculture as a fertilizer and a soil conditioner.