MHT CET202522 Apr 2025Evening ShiftChemistryCarboxylic Acid DerivativesActual
Identify the reagent used in the following reaction. aligned Benzoic acid Reagent & Benzoyl chloride + Phosphorus oxychloride & + Hydrogen chloride aligned
Options
- APCl ₃
- BHCl
- CPCl ₅
- DSOCl ₂
Correct answer
C. PCl ₅
Step-by-step solution
Benzoic acid undergoes conversion to benzoyl chloride with phosphorus pentachloride, as evidenced by the formation of phosphorus oxychloride and hydrogen chloride as byproducts. The reaction proceeds as: C ₆ H ₅ COOH + PCl ₅ C ₆ H ₅ COCl + POCl ₃ + HCl Alternative reagents yield different byproducts: phosphorus trichloride produces phosphorous acid ( H ₃ PO ₃ ), hydrochloric acid is ineffective for direct conversion, and thionyl chloride yields sulfur dioxide ( SO ₂ ). The correct reagent is therefore phosphorus pe