Explain the meaning of the term 'compound' with a suitable example. State the main characteristics of a compound with special reference to the compound iron [II] sulphide.

Compound is a pure substance composed of two or more elements combined chemically in a fixed proportion. For example, water (H₂O) is composed of two elements — Hydrogen and Oxygen in a fixed proportion by weight.

Main characteristics - with special reference to the compound iron [II] sulphide:

1. Components are present in - a definite proportion.

• Elements iron and sulphur combine in a definite proportion.

1. Compound is always homogenous.
2. Particles in a compound are of one kind.

• Composition of iron [II] sulphide, - cannot be varied, hence is uniform composition.
• Component - may not be seen separately.

1. Compound [iron [II] sulphide] has a definite set of properties.
2. Components in [Iron [II] Sulphide] do not retain their original properties and can be separated only by chemical means.

• Particles in iron [II] sulphide are chemically combined and hence -
• iron in iron [II] sulphide cannot be attracted by a magnet and does not give H₂ with dil. acid.
• sulphur present in iron [II] sulphide - is insoluble in solvent CS₂.