Compound A is prepared by the hydration of propyne in the presence of dilute H₂SO₄ and HgSO₄ . Compound B is the major product obtained by the Etard reaction of toluene. When A and B are reacted together in the presence of dilute NaOH and heated, a major product C is formed. The total number of sp^2 hybridized carbon atoms in a molecule of C is ________.

Step-by-step solution

Hydration of propyne in the presence of Hg²⁺ and H^+ (Kucherov reaction) yields acetone (A). Etard reaction of toluene using chromyl chloride ( CrO₂Cl₂ ) followed by hydrolysis yields benzaldehyde (B). Heating acetone and benzaldehyde in the presence of dilute NaOH results in a crossed aldol condensation to form benzalacetone (C). C₆H₅CHO + CH₃COCH₃ OH^-, C₆H₅-CH=CH-CO-CH₃ + H₂O In the structure of benzalacetone ( C₆H₅-CH=CH-CO-CH₃ ): The phenyl ring has 6 sp^2 hybridized carbon atoms. The alkene double bond ( -CH=