Certain non-metals and their uses are given in the wrong order in the table below. Match them correctly.

Hydrogen – Fuel

Hydrogen is a combustible gas and burns in the presence of air to produce high amounts of energy. Unlike traditional fuel sources (fossil fuels), it does not produce products that pollute the environment. It burns in the presence of oxygen to produce water and releases energy. It is widely used in fuel cells.

2H₂ + O₂→ 2H₂O + energy

Oxygen – biodegradation

Biodegradation is the process of disintegrating or breaking down of materials like remains of plants and animals by microorganisms like bacteria, fungi etc. This can happen in the presence or absence of oxygen. The process is called aerobic biodegradation, if it occurs in the presence of oxygen.

Chlorine – disinfectant

Chlorine is a very powerful disinfectant which deactivates/destroys harmful microorganisms present in drinking water, or water bodies. It can be easily applied, and is very cheap as well. It also prevents spread of contagious diseases up to an extent.

Nitrogen – refrigerant

Liquid nitrogen is used as a refrigerant. It is used to store substances at a very low temperature. This is widely used as coolants for computers, and also in cold storage units to store blood, body cells, etc. Nowadays, it has found applications in cooking as well.