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Acetylene (C₂H₂)

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An Introduction to Acetylene

Any group of organic chemical compounds is made up only of the atoms carbon (C) and hydrogen (H). The carbon atoms bind together to form the compound's framework, and the hydrogen atoms adhere to it in a variety of ways. Petroleum and natural gas are mostly made up of hydrocarbons.

Alkanes, alkenes, and alkynes are the three main families of aliphatic hydrocarbons based on the sorts of bonds they include. Alkanes have just single bonds, whereas alkenes and alkynes have a carbon-carbon double bond and a carbon-carbon triple bond, respectively.

Now we have a basic understanding of hydrocarbons and we are ready to explore acetylene. Further in this topic, we will go through some acetylene properties and acetylene formulas.

What is Acetylene?

Acetylene is the simplest alkyne chemical molecule, with the formula C2H2. Acetylene is also known by the names Ethyne, Narcylen, and Vinylene. It is widely employed as a chemical component and a fuel. It is handled as a solution in its pure form, which is unstable. It is an unsaturated molecule in which the two carbon atoms are joined by a triple bond.

Acetylene Formula

As we discussed that acetylene is the first simplest alkyne. As it is an unsaturated hydrocarbon so it must have at least two carbon atoms bonded with each other to make an unsaturated hydrocarbon or we can say a triple bond. As it is the simplest alkyne so it has exactly two carbon atoms.

As we know Alkyne has a general formula as CnH2n-2.

So for acetylene n=2.

Hence acetylene formula =× C2H2×2-2=C2H2

As per the IUPAC Nomenclature of Organic Compounds, For alkyne, we have to add “yne” as a suffix with the prefix according to the number of carbon atoms in the molecule.

So by this rule, the IUPAC name of acetylene is “Eth(prefix for 2 carbons)+yne(suffix for alkyne)”. IUPAC name of acetylene is “Ethyne”.

Acetylene Properties

Vinylene is a colourless gas with a faint ether odour. Water, chloroform, acetone, and benzene are all easily soluble in this compound. Carbon disulfide and ethanol just marginally dissolve it. It burns easily and is lighter than air. Containers can be dramatically ruptured by prolonged exposure to heat or fire.

Acetylene cannot exist as a liquid at atmospheric pressure and has no melting point. The melting point (80.8 °C) at the minimum pressure at which liquid acetylene can exist is shown by the triple point on the phase diagram (1.27 atm). Sublimation can convert solid acetylene to vapour (gas) at temperatures below the triple point. At atmospheric pressure, the sublimation point is 84.0 °C.

Acetylene is 27.9 g per kg soluble in acetone at normal temperature. The solubility of the same amount of dimethylformamide (DMF) is 51 g. At 20.26 bar, the solubility of acetone and DMF increases to 689.0 and 628.0 g, respectively. In pressurised gas cylinders, these solvents are employed.

Acetylene C2H2 Structure

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Use of Acetylene


Due to the high temperature of the flame, the industrial gases industry supplies around 20% of acetylene for oxyacetylene gas welding and cutting. Acetylene produces a flame of nearly 3,600 K (3,330 °C; 6,020 °F) when combined with oxygen, releasing 11.8 kJ/g. The hottest burning common fuel gas is oxyacetylene. The Oxyacetylene formula is also C2H2. After dicyanoacetylene's 5,260 K (4,990 °C; 9,010 °F) and cyanogen's 4,798 K (4,525 °C; 8,177 °F), acetylene is the third-hottest natural chemical flame. In former decades, oxy-acetylene welding was a prominent welding method. For many applications, the advancement and benefits of arc-based welding methods have rendered oxy-fuel welding obsolete. Welding using acetylene has become far less common. In regions where electricity is not widely available, oxyacetylene welding can be employed. Many metal fabrication shops employ oxyacetylene cutting.

Portable Lighting

The acetylene utilised in the lamps for portable or remote applications was generated using calcium carbide. It was used for miners and cavers before the widespread usage of incandescent lighting; or, many years later, low-power/high-lumen LED illumination; and it is currently used by mining industries in some countries where workplace safety standards do not exist. Carbide lamps were also widely employed as headlights in early automobiles and as a light source for lighthouses in the early 1900s.

Plastics and Acrylic Acid Derivatives

Acetylene can be converted to ethylene and used as a feedstock for a range of polyethene polymers. Acetylene's conversion to acrylic acid derivatives is another important application, particularly in China. Acrylic fibres, glasses, paints, resins, and polymers are all made from these compounds.

Niche Applications

When a steel piece is too large to put into a furnace, acetylene is occasionally used to carburize (harden) it. In radiocarbon dating, acetylene is utilised to volatilize carbon. In a small specialised research furnace, carbonaceous material in an archaeological sample is treated with lithium metal to generate lithium carbide (also known as lithium acetylide). The carbide can then be treated with water to produce acetylene gas, which can be fed into a mass spectrometer to determine the carbon-14 to carbon-12 isotope ratio.

Preparation of Acetylene

This chemical has been produced by partial combustion of CH2 since 1950. (methane). Until 1983, around 4,00,000 tonnes were produced. Friedrich Wohler discovered the reaction in 1862, and it was used to make it. The reaction of calcium carbide hydrolysis is as follows:

Ca(OH)2 + C2H2→CaC2 + 2H2O

The foregoing reaction takes place in an electric arc furnace at a very high temperature of roughly 2000 °C.

Health Hazards Due to Acetylene

People who come into touch with this chemical may experience headaches, dizziness, and loss of consciousness. Choking death can occur if there is a significant concentration of Ethyne in the air.

Last updated date: 01st Oct 2023
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FAQs on Acetylene (C₂H₂)

1. What is Acetylene?

Ans. Acetylene is the simplest or we can say the smallest Alkyne. Its chemical formula is C2H2. C2H2 chemical names are Ethyne, Narcylen, and Vinylene. Acetylene gas is used in Welding.

2. Does acetylene corrode metals?

Ans. Acetylene is colourless and has a pleasant odour in its pure form. While acetylene serves a variety of purposes, it is now known for its ability to prevent top-line corrosion in gas pipelines. Because of its high volatility, it can be sprayed as a corrosion inhibitor.

3. What happens if we inhale acetylene?

Ans. Dizziness, exhaustion, tiredness, nausea, vomiting, tachycardia, and tachypnea are all symptoms of acetylene inhalation. A high dose of acetylene exposure will cause loss of consciousness and death. Acetylene is a colourless gas that is commonly used in welding.