Gas used in welding and cutting metals:
The gas used in welding and cutting metals is ethyne, also known as acetylene. Ethyne is a hydrocarbon gas that is highly flammable and used as a fuel in various industrial processes, including welding and cutting metals.
Properties of ethyne:
- Chemical formula: C2H2
- It is a colorless gas with a distinct odor.
- It is lighter than air and highly flammable.
- Ethyne has a high flame temperature, making it suitable for welding and cutting metals.
- It is produced by the reaction of calcium carbide with water.
Role of ethyne in welding:
- Ethyne is commonly used in oxy-fuel welding and cutting processes.
- When mixed with oxygen, it produces a high-temperature flame that can melt and join metal surfaces.
- The heat generated by the ethyne-oxygen flame allows for the formation of a molten pool, which can be used to weld or cut metals.
Advantages of using ethyne:
- Ethyne has a high heat content, providing intense heat for efficient metalworking.
- It has a relatively low cost compared to other gases used in welding and cutting.
- Ethyne can be easily compressed and stored in cylinders for easy transportation and use.
Disadvantages of using ethyne:
- Ethyne is highly flammable and requires careful handling and storage.
- It has a narrow range of flammability and can form explosive mixtures with air.
- The production of ethyne involves the use of calcium carbide, which can be hazardous if not handled properly.
In conclusion, ethyne (acetylene) is the gas commonly used in welding and cutting metals due to its high flame temperature and ability to generate intense heat. It is important to handle and store ethyne with caution to ensure safety in industrial processes.

When ethyne is burnt in oxygen, a large quantity of heat along with light is produced. The heat evolved can be used for gas welding which is usually carried to weld small broken pieces of articles made up of iron.


C2H2(g)+5/2O2(g). gives rise to 2CO2(g)+H2O(l)+ heat and light.


Air mainly contains a mixture of nitrogen 4 parts and oxygen 1 part. Aswer know, nitrogen gas does not support combustion. This means that in air , only oxygen will help in the combustion of ethyne. Therefore, it is always better to use oxygen for the combustion of ethyne to facilitate complete combustion.

Ethyne is the third hottest natural chemical flame.It is supplied by industrial gases industry for welding and cutting due to high temperature of the flame,combustion of acetylene with oxygen produces a flame over 3600K.It is the hottest burning common fuel gas.