Salt is an ionic compound that occurs from the neutralisation of acids and bases. Salts are formed by positively charged ions (known as cations) and negatively charged ions (known as anions), which may be organic or inorganic in nature. These ions are present in a proportional quantity, thereby making the nature of the salt neutral. 

It is found in significant amounts in seawater, where it is the main mineral component. Salt is important to animal life, and saltiness is one of the simple human tastes. Salt is an ionic compound with a cation other than H+ and anion other than OH– and is generated along with water in the neutralisation reaction between acids and bases.

• Acid salt: Salt formed by partial neutralisation of diprotic or polyprotic acid is known as acid salt. These salts, along with another cation, have ionisable H+ ion. The ionisable H+ is mostly part of the anion. Some acid salts are used for baking. For example—NaHSO4, KH2PO4, etc.
• Basic or alkali salt: Salt formed by partial neutralisation of a solid base of a weak acid is known as basic salt. They are hydrolysed to form a simple solution. That is that when the hydrolysis of the basic salt occurs, the conjugate base of the weak acid is formed in the solution—for example—white lead (2PbCO3·Pb(OH)2).
• Double salts: Salts with more than one cation or anion are known as double salts. They are obtained by the synthesis of two separate salts crystallised in the same ion lattice. For example—Potassium sodium tartrate (KNaC4H4O6.4H2O), also known as Rochelle salt.
• Mixed Salts: Salt consisting of a fixed proportion of two salts, sometimes shared by either a common cation or a common anion, is known as mixed salt. For example—CaOCl2

The compound sodium chloride has very different properties from the sodium and chlorine elements.

• Saltwater comprises ions and is a relatively good conductor of electricity.
• This electrostatic attraction force binds the ions together, and a chemical bond is said to form between them.

The procedure used for laboratory preparation of salt relies on the solubility of the salt in the water. A soluble salt can be prepared by a reaction between an acid and a metal, a base or a carbonate.

• Acid + alkali gives salt + water.
• Acid + metal gives salt + hydrogen.
• Acid + salt gives salt + water.
• Acid + metal carbonate gives salt + water + carbon dioxide.

Chemical decomposition is the splitting or dissolution of a single chemical compound into simpler compounds or their elementary components. This can be described as the exact opposite of chemical synthesis. For example:

• Electrolysis of water into oxygen and hydrogen: 2 H2O(I) into 2H2 + O2
• As carbonates are heated, decompose: H2CO3 into H2O + CO2
• Chemical decomposition of calcium carbonate: CaCO3 into CaO + CO2
• Decomposition of metal chlorates when heated: 2 MClO3 into 2 MCl+ 3 O2

In this chapter, we learnt about the concepts of acids, bases and salts. We also learnt about the types and properties of salts. The chapter also gave us knowledge of the laboratory preparation of salts.

1. Why do HCl, HNO3, etc., exhibit acidic characters in aqueous solutions?
2. The release of H+ ion in water will make a compound acidic or non-acid. Acids are a compound that results in the formation of hydrogen ions when dissolved with water. Some molecules have an acidic character when they dissolve in the aqueous solution, resulting in the release of hydrogen ions (acids like HCl, HNO3).
3. Why do solutions of compounds such as alcohol and glucose not show acidic character?
4. Compounds like glucose or alcohol do contain hydrogen elements but do not exhibit signs of an acidic disposition. The fact that the hydrogen in them would not differentiate like the hydrogen in the acids. They’re not going to split to become hydrogen ions, dissolving in water.
5. Why does an aqueous acid solution is a conductor of electricity?
6. The charged particles are responsible for the conductivity of the electricity in the acid. These charged particles, called ions, are the cause for the conductivity of electricity in acid.
7. Why does dry HCl gas not affect the colour of dry litmus paper?
8. HCl does not emit hydrogen ions, so HCl does not exhibit any acidic behaviour, and the colour of the litmus paper remains the same when reacting with HCl gas.
9. Why should curd and sour compounds not be stored in brass and copper vessels?
10. Curd and sour food compounds contain acids; these acidic substances often combine with metal. This reaction transforms food into a toxin that damages people’s health.