ICSE Class 8 Answered
ACIDS
Acids derived from minerals are called inorganic acids or mineral acids.
Examples: Hydrochloric acid, sulphuric acid, nitric acid
Acids derived from plants are called organic acids.
Examples: Tartaric acid, citric acid
An acid is a compound which when dissolved in water produces hydronium ions (H3O+).
HCl(aq) + H2O → H3O+ + Cl–(aq) Hydrochloric acid Water Hydronium ion Chloride ion |
BASES
Bases are chemical substances with a bitter taste and are soapy to touch.
They are oxides or hydroxides of metals which react with acids to give salt and water.
Alkalis
- Alkalis are bases which are soluble in water.
- All alkalis are bases, but all bases are not alkalis. This is because certain bases are insoluble in water.
An alkali is a compound which when dissolved in water yields hydroxyl ions (OH−) as the only negatively charged ions.
SALTS
- A neutralisation reaction involves a reaction of a base with an acid to give salt and water only.
NaOH + HCl → NaCl + H2O Base Acid Salt Water |
Therefore, a salt is defined as a compound formed from an acid by partial or complete replacement of hydrogen ions (H+) of an acid by a metallic ion (basic radical) or an ammonium ion.