Question

CaC2 + H2O _ Red hot Fe tube

• A. Acetylene
• B. Ethane
• C. Benzene
• D. Ethene

Answer 1

Answer: (C)

Benzene ($C_6H_6$)

Answer 2

The reaction proceeds in two steps:

1. Calcium carbide ($CaC_2$) reacts with water ($H_2O$) to produce acetylene ($C_2H_2$). $CaC_2(s) + 2H_2O(l) \rightarrow C_2H_2(g) + Ca(OH)_2(aq)$
2. Acetylene ($C_2H_2$) undergoes cyclotrimerization when passed through a red-hot iron tube, forming benzene ($C_6H_6$). $3 C_2H_2(g) \xrightarrow{Red \ hot \ Fe \ tube} C_6H_6(g)$

The final product is Benzene.