Oxygen: Laboratory and Industrial Preparation

Laboratory Preparation of Oxygen

Oxygen can be prepared in the laboratory through the decomposition of hydrogen peroxide $(\text{H}_2\text{O}_2)$ using manganese(IV) oxide $(\text{MnO}_2)$ as a catalyst.

The reaction is as follows:

• $2\text{H}_2\text{O}_2 (aq) \xrightarrow{\text{MnO}_2} 2\text{H}_2\text{O} (l) + \text{O}_2 (g)$

The oxygen gas produced is collected over water.

Key Points

• Hydrogen Peroxide: The source of oxygen in this reaction.
• Manganese(IV) Oxide: Acts as a catalyst to speed up the reaction.
• Collection: Oxygen is collected by displacement of water.

Industrial Preparation of Oxygen

Oxygen is produced industrially through the fractional distillation of liquefied air. This process separates the components of air based on their boiling points.

Steps in Fractional Distillation of Air

1. Compression: Air is compressed to a high pressure.
2. Cooling: The compressed air is cooled to around -200°C, turning it into a liquid.
3. Distillation: The liquid air is slowly warmed in a fractional distillation column. Different gases boil off at different temperatures:
• Nitrogen: Boils off first at -196°C.
• Argon: Boils off next at -186°C.
• Oxygen: Boils off last at -183°C.

Key Points

• Separation: Based on different boiling points of gases in air.
• Efficiency: Fractional distillation allows for the efficient separation of gases.