Question

Benzoic acid to Benzene

Hint:

Soda lime decarboxylation removes –COOH as CO\(_2\) → gives hydrocarbon.

Answer 1

Concept: Benzoic acid can be converted to benzene by
decarboxylation. This removes the carboxyl group as CO\(_2\).
Step 1: Soda lime decarboxylation. Heat benzoic acid with soda lime (NaOH + CaO): \[ C_6H_5COONa + NaOH \xrightarrow{CaO,\ \Delta} C_6H_6 + Na_2CO_3 \]
Step 2: Formation of sodium salt first. \[ C_6H_5COOH \xrightarrow{NaOH} C_6H_5COONa \]
Final Conversion: \[ \text{Benzoic acid} \xrightarrow{\text{soda lime}} \text{Benzene} \]