Question

How is bezene prepared from ethyne

Answer 1

Step 1 -->
 Convert ethane to ethyne

ETHANE --- cl2 sunlight --> CH3CH2CL
Ethyl Chroride --- KOH(alc.) Heat -----> Ethene
Ethene -------- Br2 + CCL4 ---> BrCH2CH2BR
Ethylene Dibromide ------ 2KOH(Alc.) + Heat ----> Ethyne




Step 2-->
Pass 3 moles of ethyne from red hot iron/copper tube at 778K to get 1 mole of benzene.
  3 C2H2 --------->>>> C6H6

Hope it helps

Answer 2

To prepare benzene (C6H6) from ethyne (C2H2), a process called cyclic polymerization is used. This is where the ethyne is passed through an iron tube that is red hot, at around 873 kelvin. This is what causes the ethyne molecule to undergo cyclic polymerization, which forms benzene.