Oxygen & Sulphur

Oxygen

Symbol : O,
Molecule formula — O₂,
Atomic Number — 8,
Mass Number — 16
Element - P-block

Occurrence and Preparation of Oxygen Gas :
» Oxygen gas was firstly invented by a Sweden based scientist Scheele in 1772.
» It is a colourless, odourless gas, which is slightly heavier than atmospheric air.
» It reduces into a deep blue liquid on cooling, it doesn’t bum itself but favours the process of combustion.
» A mixture of helium and hydrogen gas is used in the artificial inhalation.

» There are three isotopes of oxygen — ₈O¹⁶, ₈O¹⁷, and ₈O¹⁸

Sulphur

Symbol: S,
Atomic Number —16,
Mass Number — 32

Allotropes of Sulphur

1. Crystalline Allotropic Forms :
    (a) Rhombic or Octahedral or a-sulphur
    (b) Prismatic or Monoclinic or p-sulphur

2. Non-crystalline Allotropic Forms :
    (a) Plastic sulphur
    (b) White sulphur
    (c) Milky sulphur

Compounds of Sulphur

1. Sulphur Dioxide (SO₂) :
During volcanic eruption, the main gas which releases is sulphur dioxide, and it is a colourless, suffocating, and a gas of bitter smell. This gas is also used as an antichlor. It exhibits the property of bleaching action, but it is temporary. The structure of SO₂ is angular.

2. Sulphuric Acid (H₂SO₄) :
It is called chemical king of all the acids, and it is also known as oil of vitriol. On the industrial level, H₂SO₄ is manufactured by two processes-Contact process and Lead Chamber process.

3. Hydrogen Sulphide (H₂S) :
During volcanic eruption, hydrogen sulphide gas is also released in small amount. This is basically a colourless gas, which is poisonous (toxic), and its smell is like rotten eggs.