Acids, Bases, Oxides | Chemistry | CSEC CXC lessons online – Study Guide


Tribasic Acids

Tribasic acids produce 3 moles of H+ ions per mole of acid.


Acid Anhydrides

An acid anhydride is an acidic oxide of a non metal which reacts with water to form an acid.

Note: The double sided arrow is used for a reaction which is reversible, that is, total ionization does not take place and the reactants can easily be reformed.

The single arrow  is used for an irreversible reaction, that is, total ionization has taken place, and the reactants do not reform.



A base is chemically opposite to an acid and may be defined in two ways:

  1. A base is a substance which will react with an acid to form a salt and water only.
  2. A base is a proton (H+) acceptor.

Bases include ammonia and most metallic oxides.


An alkali is a base which dissolves in or reacts with water to form a solution which contains OH- ions.

Alkalis are Na2O,  K2O,  NaOH,  KOH.


Acidic Oxides

These are the Oxides of non metals. They dissolve in water to form acids therefore often referred to as acid anhydrides.


Basic Oxides

These are the Oxides formed by most metals. They react with acids to give a salt and water only.


Amphoteric Oxides

These are oxides which can react with both acids and bases to form salts, that is, they can act as either an acid or a base. They are formed by some metals, including, Aluminum, Lead and Zinc.

Solubility Characteristics


All Nitrates are soluble. Example: KNO3,  NaNO3,  AgNO3.

All Chlorides, Bromides and Iodides are soluble except AgCl and PbCl2.



All Oxides and Hydroxides are insoluble except, K2O,  Na2O,  CaO,  KOH,  NaOH,  Ca(OH)2

All Carbonates are insoluble except K2CO3,  NaCO3,  (NH4)2CO3.


Web links for further information:



Lambert, Mohammed, Norman, Marine. Chemistry for CXC: Completely Revised New Edition. Oxford: Heinemann, 1993.