Programmes/ Content/ Chemistry

Compound of Metals



  • By direct combination of metal and oxygen:

-Almost all metal oxides can be prepared by this method.

  • By decomposition of carbonates, sulphates, nitrates

  • Roasting of Sulphide ore:

  • Metal with hot water or steam



-Alkali oxide are soluble in water except which is partially soluble in water.

-Alkaline earth metal oxides are sparingly soluble in water.

-Other oxides are insoluble in water.

Action of heat:

-Almost all metal oxides are thermally stable except and

Types of oxides:

Basic Oxide:

-Reacts with acid to form salt and water.

-They are metallic oxides.

-Eg:, etc.

-They changes red litmus paper to blue.

Acidic Oxides:

-Reacts with base to form salt and water.

-They are non-metallic oxides.


-They changes blue litmus to red

Neutral Oxide:

-Shows neither acidic nor basic character.

-Neutral towards litmus test.

-Eg: etc.

Amphoteric Oxide:

-It is metallic oxide of few metals, which can show both acidic and basic properties.

-Reacts with both strong acid and alkali to produce salt and water.

-Eg: etc.

Peroxide and Superoxide:


-Treated with dil. acid to yield .

-Oxidation state of oxygen on peroxide is .



-Treated with dil. acid to yield and .

-Oxidation state of oxygen on superoxide is .

-Eg: etc.

Mixed Oxides:

-Oxides which are the mixture of two or more oxides.

-Eg: etc

- is the mixture of and


-Contain lesser number of oxygen than required according to valency.

-Eg: , etc.