Revision: Acids, Bases and Salts Science SSC (English Medium) 9th Standard Maharashtra State Board

The force of attraction between cation and anion is called as the ionic bond.

The compounds formed from two units, namely cation and anion are called ionic compounds.

It is the fixed amount of water that is present in a crystal as an integral part of its constitution. Hydrated salts are salts having water of crystallisation.

It is the phenomenon by which hydrated salts, on exposure to dry air, lose their water of crystallization and crumble to powder.

It is the phenomenon by which substances absorb moisture from air, but only sufficiently so as to become wet.

Salt is a compound formed by the partial or total replacement of the ionisable hydrogen atoms of an acid by a metallic ion or an ammonium ion.

Normal salts are the salts formed by the complete replacement of the ionizable hydrogen atoms of an acid by a metallic or ammonium ion.

For example: Sodium chloride (NaCl), Na₂SO₄.

The salt formed by the partial replacement of the replacable hydrogen atoms of an acid molecule by a metallic or ammonium ion is called acid salts.
For example: NaHSO₄ , Na₂HPO₄

It is the process of decomposition of a chemical compound in aqueous solutions or in a molten state accompanied by a chemical change using direct electric current. 

Electrolysis :
It is the process of decomposition of the electrolyte in the molten or aqueous state by discharge of ions at the elctrodes on passage of an electric current.

It is the process of decomposition of an electrolyte in the molten or aqueous state by discharge of ions at the electrodes on the passage of an electric current.

The amount of heat energy required by ice to change into water is called the latent heat of fusion of ice.

• Ionic compounds are made of positive and negative ions held by electrostatic force.
• They are neutral overall as charges of ions balance each other.
• They are hard, brittle, and crystalline due to a regular ion arrangement.
• They have high melting and boiling points because of the strong attraction between ions.
• They dissolve in water and conduct electricity when molten or in solution, but not when solid.

• Normal salts – All hydrogen ions of the acid are replaced (e.g., NaCl, Na₂SO₄).
• Acid salts – Formed when only some hydrogen ions are replaced (e.g., NaHSO₄).
• Basic salts – Formed when only some OH⁻ ions are replaced (e.g., Pb(OH)Cl).
• Double salts – Made by combining two salts that crystallise together (e.g., Mohr’s salt).
• Mixed & Complex salts –
  • Mixed: Have more than one acid/base radical (e.g., NaKCO₃)
  • Complex: Give a complex ion on dissociation (e.g., [Ag(CN)₂]⁻)