Question

Explain the chemical equation. What happens when: passing acetylene gas in a red hot tube?

Answer 1

Hint: The reaction involved in passing acetylene gas in the red hot tube is chain polymerization reaction. In this reaction the small monomer molecule polymerizes by itself to give a large molecule.

Complete step by step answer:
Acetylene is also known as ethyne. The chemical formula of ethyne is ${C_2}{H_2}$. By the suffix –yne only it can be assumed that it contains a triple bond. In acetylene, two carbon atoms are present and both the carbon atoms are bonded to each other by triple bond.
When acetylene is passed through a red hot tube benzene is formed. This reaction takes place by a chain polymerization process. Polymerization is a process where a small molecule commonly known as monomer joined together to form a large network molecule. Chain polymerization is a type of polymerization reaction where the small monomer unit combines with each other to give a large molecule.
The reaction taking place when acetylene is passed through the red hot tube is shown below.

In this reaction three molecules of acetylene are passed through a red hot tube at the temperature of 873 k after which the molecule reacts with each other and polymerizes to form a six membered ring structure known as benzene. The chemical formula of benzene is ${C_6}{H_6}$.

Note: The reaction between acetylene and red hot tube is also known as trimerization as three molecules of acetylene are used which combine to give benzene. The red hot tube is made up of iron.